THE STABILIZATION OF TUNGSTEN(VI) ALKYLS, ALKYLIDENES,
AND HYDRIDES USING A BIDENTATE BIS-AMIDE LIGAND
By
DANIEL D. VANDERLENDE
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNTVERSITY OF FLORIDA
1994
-.._
,\/27$
ACKNOWLEDGEMENTS
The people deserving thanks from the author for the completion of this dissertation
are innumerable. A great debt is owed to Dr. Jim Boncella, who has guided the author
through this adventure. The lessons taught by Jim will have an influence on the rest of the
author's life. He not only challenged and motivated the author, he also brought out the best
in the author's golf game, teaming with Larry Villanueva and William Vaughan to win the
1993 Analytical Open.
Special thanks goes to Dr. Khalil Abboud. Dr. Abboud solved or helped the author
solve all of the crystal structures reported in this dissertation. He taught the author
everything the author knows about crystallography. The author is grateful for the patience
and enthusiasm Dr. Abboud showed throughout the research which was the basis for this
dissertation, exemplified by the eleventh hour structure included in Chapter 4 .
There were many people who passed through the Boncella lab during the author's
tenure. Everyone of these people played a role in the completion of this dissertation.
Those who have since moved on, Larry, Laura Blosch, Scott Gamble, and Gaines Martin,
were positive role models who taught by example how to work hard in a fun group
environment. Will Vaughan has been a constant source of fun, excitement, and intellectual
stimulation over the past four plus years.' The author would also like to remember all the
other members of the Boncella group who have made research so stimulating; Percy
Doufou, Jerrold Miller, Mary Cajigal, Justine Roth, Jon Penney, Steve Wang and Faisal
Shafiq. Who could ever forget Tegan Eve and Melissa Booth?
Special thanks also goes to Mike Cruskie and Chris Marmo who have been great
friends and fellow chemists over the years. A special thanks also goes to the Talham
group, especially John Pike and Houston Byrd, who both shared their unique perspectives
ii
on life with the author. The author is also indebted to the people who made the research
possible on a daily basis; Dr. King, Charlie Cromwell, Rudy and Vern.
None of this would have been possible without my parents who instilled in their
son the desire to never be satisfied with past accomplishments. The author would like to
acknowledge the love and devotion of the "Coach". He was always there for the author,
displaying undying devotion and loyalty. Lastly, the author would like to acknowledge his
wife Michelle, who has been the driving force behind the completion of this dissertation.
Michelle has always believed that there is nothing her husband cannot accomplish, and that
belief has motivated the author to strive to be more than he ever thought he could be,
because maybe she is right.
in
TABLE OF CONTENTS
ACKNOWLEDGEMENTS H
ABSTRACT vi
CHAPTERS
1 BACKGROUND AND INTRODUCTION 1
1.1 High Oxidation State Transition Metal Chemistry Involving Ligand Metal
Multiple Bonds 1
1.2 Olefin Metathesis and Olefin Metathesis Polymerization 4
1.3 Chelate Stabilized Alkylidenes 8
1 .4 Polydentate, Polyanionic Ligands 11
2 SYNTHESIS OF BIS-AMIDE CHELATE LIGANDS AND LIGAND
METAL COMPLEXES 13
2.1 Preparation of Bidentate Ligands 13
2.2 Synthesis of New Ligand-Metal Complexes 16
3 SYNTHESIS AND REACTIVITY OF W(VI) ALKYLS AND
ALKYLIDENES 27
3.1 Background Information on W(VI) Alkyls and Alkylidenes 27
3.2 Synthesis of W(VI) Bis- Alkyl Complexes 29
3.3 Alkylidene Formation From Bis-Alkyl Complexes 36
3.4 Metathesis Activity of W(NPh)(CHCMe3)(PMe 3 )[(Me 3 SiN)C6H4], 36 46
4 FORMATION OF W(VI) HYDRIDES FROM THE BIS-ALKYL
COMPLEXES 55
4. 1 High Oxidation State Transition Metal Hydride Complexes 55
4.2 Preparation of W(VT) Hydride Complexes 55
4.3 Reactivity of the Dihydrides 69
5 EXPERIMENTAL 75
APPENDICES 87
A TABLES OF NMR DATA 88
B TABLES OF CRYSTALLOGRAPHIC DATA 103
REFERENCES 147
IV
BIOGRAPHICAL SKETCH 153
Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
THE STABILIZATION OF TUNGSTEN(VI) ALKYLS, ALKYLIDENES,
AND HYDRIDES USING A BIDENTATE BIS-AMTDE LIGAND
By
Daniel D. VanderLende
December, 1994
Chairman: James Boncella
Major Department: Chemistry
The synthesis of a number of W(VI) complexes stabilized by bis-amide chelate
ligands was achieved with the goal of preparing new olefin metathesis polymerization
catalysts. Addition of Li 2 [(NSiMe3)2C6H4] 2, to W(NPh)Cl4(OEt2) yields
W(NPh)Cl2[(NSiMe3)2C<5H4] 14. A single crystal diffraction study of 14 reveals that it
crystallizes in the space group P 2]/n with a = 10.294(2) A, b = 17.859(3) A, c =
12.565A, (3 = 104.15(2)°, V = 2384.6(8) A3, Z = 4. The structure of 14 is unique in that
the ligands phenyl ring is in close contact with the metal center, with a fold angle of 53°.
Addition of PMe3 to 14 affords the purple mono-adduct,
W(NPh)Cl2(PMe3)[(NSiMe 3 )2C6H4] 21. A single crystal diffraction study of 21 reveals
that it crystallizes in the space group P_i with a = 9.562(1) A, b = 10.277(1) A, c =
14.920(2) A, a = 82.15(1)°, (3 = 80.18(1)°, y = 80.41(1)°, V = 1415.6(3) A3, Z = 2.
Compound 14 can be alkylated to give the corresponding bis-alkyls,
W(NPh)R2[[(NSiMe3)2C6H4]. The 14 electron bis-alkyl compounds show no evidence of
a-agostic W-H-C interactions and have ^Ca-H values between 120 and 130 Hz.
VI
W(NPh)(CH2CMe3M(NSiMe3)2C6H4] 25 can be heated in the presence of excess PMe3
to give the new alkylidene complex, W(NPh)(CHCMe3)(PMe3)[(NSiMe 3 )2C6H4], 36.
Compound 36 crystallizes in the space group P 2\lc with a = 16.1 16(3) A, b = 1 1.340(2)
A, c = 17.960(4) A, (3 = 106.28(2)°, V = 3151(1) A 3 , Z = 4. The x-ray structure of 36
reveals a unique square pyramidal structure with the alkylidene carbon in the apical
position. Compound 36 is an active ROMP catalyst, polymerizing twenty five equivalents
of norbornene in ten minutes at room temperature. The reactivity of the catalyst can be
altered by the addition of excess PMe3 to the reaction mixture.
W(NPh)(CH2CMe3)2[(NSiMe3)2C6H4] 25 reacts with molecular hydrogen in the
presence of PMe3 to give the seven-coordinate dihydride complex,
W(NPh)H2(PMe3)2[(NSiMe3)2C6H4] 39. The dihydride reacts with two equivalents of
ethylene or styrene to give the W(IV) olefin complexes W(NPh)(r| 2 -
C2H4)(PMe3)2[(NSiMe3)2C 6 H4] 46, and W(NPh)(r|2-
CH2CHPh)(PMe3)2[(NSiMe3)2C6H4] 47. The olefin complexes react with H 2 ,
hydrogenating the olefin and forming the dihydride, 39.
vu
CHAPTER 1
BACKGROUND AND INTRODUCTION
1.1: High Oxidation State Transition Metal Chemistry Involving
Metal Ligand Multiple Bonds.
There has long been an interest in the isolation of high oxidation state transition
metal complexes. 1 The term high oxidation state transition metal refers to transition metals
which are in their highest or nearly highest oxidation state. Throughout this discussion,
high oxidation state transition metals will usually refer to transition metals with zero d
electrons, or d° complexes. The applications of high oxidation state transition metal
complexes are innumerable. A plethora of reactions are catalyzed by such compounds 1 - 2
oxidations, metathesis, polymerizations and many organic transformations. Therefore, the
synthesis of novel compounds and investigation of their properties and reactivity are
essential in order to expand our understanding of high oxidation state transition metal
chemistry.
High oxidation state transition metals were being used in many applications long
before the intrinsic characteristics or the structure of discrete molecules were known. 3 In
other words, high oxidation state transition metal complexes have been used as
heterogeneous catalysts and homogeneous catalysts for decades, but, in order to expand
our understanding of the reactions catalyzed by these compounds, the identity of the
discreet molecules must be known. Often times, the active species in the reaction is
different that the starting compound, and hence the structure of the active species is
unknown or unproven. 3 Many high oxidation state transition metal complexes contain
multiply bonded atoms; nitrogen, oxygen, and carbon are the most common. 2 Also, the
active species in many catalytic processes are postulated to contain metal-ligand multiple
bonds. 3 ' 4 Often, these multiply bonded ligands are the key to the reactivity or stability of
the molecules. Therefore, the synthesis and structural elucidation of new multiply bonded
ligand-transition metal complexes will always be relevant.
Examples of transition metal oxo 5 [O] 2 ", imido 6 [NR] 2 ~ and nitrido 7 [N] 3 ~
complexes are numerous. Books and reviews on these types of ligands can be found
throughout the literature. The chemistry of high oxidation state transition metal-carbon
multiple bonds, alkylidenes [CHR] 2 " and alkylidynes [CR] 3 ", are rapidly becoming better
understood, yet relatively few examples compared to oxo or imido complexes are known. 8
The bonding in oxo, imido, and alkylidene complexes share some common characteristics.
They all involve a metal ligand G-bond and one or more rc-bonds between the ligand/?
orbitals and the empty metal d orbitals. 1 ' 8 ' 9 In oxo and imido complexes, a lone pair of
electrons can also form a second 7t-bond to the metal center. In imido complexes, this is
evident in the fact that for most of the structurally characterized compounds, the M-N-C
bond is nearly linear, greater than 160 . 1 ' 8 The bond is considered a six-electron donor and
a di-anionic contribution from the ligand, creating a formal bond order of 3, Figure 1.1.
In alkylidenes, there is not an extra pair of electrons, therefore, the bond is considered as
one a and one 7t-bond, a four-electron [-2] donor, with a formal a bond order of 2, Figure
1.2. This interaction between the ligand ji and metal d
M=N R
Figure 1.1. Figure 1.2.
Bonding in imido complexes. Electronic interactions in alkylidenes.
orbitals leads to a stabilization of the complex due to electron donation to the empty orbitals
on the dP metal center. 1 ' 9 For this reason, many of the known high oxidation state
compounds contain one of the multiply bonded ligands mentioned. Figure 1.3 shows
how the number of publications in this field of research has grown in just a few decades. 1
It should be recognized that the table does not include oxo complexes, work on which is
published at roughly an order of magnitude greater than the others combined.
200
I
1
1
1
100 -
1960 1965 1970 1975 1980 1985
Period Ending
Figure 1.3. Graph of imido and alkylidene publication rates.
It would be difficult and unnecessary to give a complete review of high oxidation
state transition metal complexes with multiply bonded ligands in this introduction.
Therefore some restraints will be put on the background information. The information
relevant to the research that was carried out pertains to W(VI) oxo, imido, and alkylidene
compounds. Therefore this discussion will be limited to examples of these and other
closely related compounds for direct comparison to the tungsten derivatives. Although
numerous new W(VI) imido and a few oxo compounds were isolated as a result of this
work, in every instance they behave as spectator ligands. They play an important role in
the electronic stabilization of the complexes but do not participate directly in any reactions.
This will become more evident in the discussion of the research results.
1.2 Olefin Metathesis and Olefin Metathesis Polymerization
The initial goal of this project was the isolation of thermally stable, coordinatively
unsaturated alkylidene complexes. These new complexes were then intended to catalyze
specialized metathesis polymerization reactions. And although this goal was attained in
part, many novel, unrelated aspects of high oxidation state chemistry were observed along
the way.
In just the last two decades, the important role of transition metal alkylidene
complexes in olefin metathesis reactions has been thoroughly investigated. 10 ' 11 The olefin
metathesis reaction, in general, can be described as the net breaking of carbon-carbon
double bonds, and forming two new carbon-carbon double bonds Figure 1.4. The
R R"
R H H R" \ /
\s V • , > <
transition metal
catalyst
H
H
+
H
H
R' H H R'"
<
R R"
Figure 1.4. Scheme showing the net conversion observed in
olefin metathesis reactions.
overall result is the exchange of substituents on the olefins. It was the suggestion by
Herrison and Chauvin 12 in 1970 that the mechanism for olefin metathesis involves an
alkylidene bond Figure 1.5. An olefin can then coordinate to the electrophilic metal
center. An intermediate metallacyclobutane is formed which can either cleave to give the
original alkylidene/olefin complex or cleave to give a new olefin complex.
rMi < ' V/\ [M] <^
y=<y "S6 H H > = =< ,
ST R" R^H R R "
Figure 1.5. The Chauvin mechanism for metathesis involving metal alkylidenes with
arrows depicting the direction of electron flow for productive metathesis.
This mechanism gained wide acceptance and seemed quite plausible for systems such as the
popular olefin metathesis catalyst, WOCl4/EtAlCl2, where the formation of an initial
tungsten ethylidene complex 3 is easy to rationalize Figure 1.6.
o
ci^y^-^ -CH3CH3, ci>
o
w^ + 2EtAlCl 2 < MC[ &
ci /
cS
w <^
H
CH 3
c/
Figure 1.6. The proposed formation of an ethylidene complex
in the WOCI4/E1AICI2 system.
Postulation and speculation about alkylidene formation officially ended on July 27,
1973, when Schrock 13 at I. E. du Pont Central Research synthesized
Ta(CHCMe3)(CH2CMe3)3. Since that time, numerous other alkylidene complexes have
been isolated and have been shown to be active catalysts for metathesis and metathesis
polymerization reactions. In the early 1980s, tungsten and molybdenum alkylidenes
received special attention since they are highly active olefin metathesis catalysts. The fields
of olefin metathesis and olefin metathesis polymerization received a boost in 1989 when
Schrock published the detailed synthesis 14 of W(NAr')(CH-t-Bu)(OR) 2 (Ar' = 2,6-'Pr 2 Ph;
OR = O-t-Bu, OCMe 2 (CF 3 ), OCMe(CF 3 ) 2 ). The W(NAr')(CH-t-Bu)(OCMe(CF 3 ) 2 )2
derivative has proven to be the most active alkylidene catalyst to date. Recently, the
molybdenum r-butoxide derivative has become available commercially from Strem
Chemical, through Catalytica, albeit for a hefty price.
Schrock's tungsten and molybdenum catalysts have some unique features which
lend to the high reactivity which has been observed. In order to design a new or better
catalyst, certain features must be retained. Obviously Schrock's catalyst involves Group
(VI) metals in the 6+ oxidation state. That the catalysts are only four coordinate is essential
since coordination of the olefin to the metal center is the initial step in metathesis. The
imido moiety's role is crucial. There are examples of oxo-alkylidene's where the role of
the oxo is identical to the imido. 15 Of the known tungsten and molybdenum alkylidenes,
examples without an imido or oxo ligand are less common. 16
The imido functionality offers a great electronic stabilization to the metal center.
The bonding can be thought of as a a bond and two 7t bonds, the second n bond arising
from donation of the lone pair of electrons on the imido nitrogen to an empty metal d
orbital. The imido functionality can also stabilize the complex by adding steric bulk to the
metal center. Most of the known alkylidene complexes contain 2,6-disubstituted aryl imido
ligands. 8 The other substituents also contribute to the steric bulk around the metal center.
All of the alkoxide substituents are rather bulky, and the alkylidene substituent is usually a
bulky alkyl group. The steric bulk is necessary since these complexes are known to
dimerize forming bridging alkylidenes. 8 The bulky metal center reduces the probability of
this transformation. The steric bulk also plays a role in the formation of the alkylidene
itself. A large percentage of the known alkylidenes are formed through a-hydrogen
abstraction reactions from dialkyl precursors or intermediates. 8 The steric bulk helps
promote the a-abstraction, usually of a bulky alkyl substituent. The reactivity of the
alkylidene catalysts is observed to increase as the electron withdrawing nature of the
alkoxide is increased, O-t-Bu < OCMe2(CF3) < OCMe(CF3)2). 8 This is intuitive since the
electron withdrawing nature of the alkoxide would make an already electron deficient
molecule more so, thereby increasing the olefin affinity, which, as was mentioned before,
is the initial step in olefin metathesis.
As was mentioned earlier, these alkylidene catalysts can facilitate the polymerization
of olefins. 10 >! 1 The most common metathesis polymerization reaction is Ring Opening
Metathesis Polymerization (ROMP). 10 The ROMP reaction is driven by the relief of ring
strain in cyclic olefins. Since olefin metathesis reactions are actually series of equilibria,
the opening of a strained ring prohibits the reverse reaction, driving the polymerization. 10
The overall ROMP reaction is shown in Figure 1.7. A large volume of work has been
done on the ROMP reaction. Norbornene, NBE, is commonly used as the olefin since it is
readily polymerized by a large number of catalysts. Schrock and Grubbs have
demonstrated that many ROMP reactions are living' polymerizations. 17
A unique olefin metathesis polymerization reaction which was developed here at the
University of Florida involves acyclic dienes. 1 ^ The net reaction for acyclic diene
H R H
= "h
H
M=C( +
R
o
^ M
R
Figure 1.7. The ring opening metathesis polymerization of a cyclic olefin.
metathesis polymerization (ADMET) can be seen in Figure 1.8. The equilibrium is
driven toward polymer formation by the removal of ethylene, or another small, volatile,
olefinic molecule, from the reaction mixture. ADMET polymerization has long been the
driving force in the research efforts of the group. ADMET reactions are best carried out in
neat monomer in order to maximize the olefin concentration and to prevent side reactions.
One of the major hindrances in this chemistry is precipitation of the reaction mixture before
the polymerization can be carried to high molecular weight. As an example, when
poly(octene) reaches twelve connections in neat 1,9-decadiene, precipitation occurs.
Performing the reaction at a temperature above the melting point of the polymer would
alleviate this problem. However, at this point, the thermal stability of the catalyst becomes
crucial. Schrock's catalyst is thermally unstable, so, although the Schrock catalyst has
proven efficient for ADMET, achieving high molecular weight polymer is difficult.
M:
H
:Q +
R
+ C 2 H,
Figure 1.8. The ADMET Polymerization of 1,9-Decadiene
8
The principles of ADMET have also been applied to depolymerizing unsaturated
polymers. 19 Since all the steps of ADMET are reversible, reacting the polymer, another
olefin, and catalyst should depolymerize a poly-ene such as polybutadiene. Success has
been found when polybutadiene is depolymerized using Schrock's catalyst and end-capped
with silylenes. This reaction will be discussed more in Chapter 3.
Although the Schrock catalyst described above represents the ideal at this time,
there are shortcomings involved in its preparation and reactivity. From first-hand
observations, it has been observed that the preparation of Schrock's catalyst is a lengthy,
patience-trying procedure. Not only are there multiple steps involved, but the yields are
low and some of the reagents are far from inexpensive. Secondly, once synthesized, the
catalysts, especially the fluorinated alkoxides, are particularly air/moisture sensitive. This
aspect of its reactivity also translates into an intolerance of certain functional groups. A
common phrase heard in polymer laboratories is "The catalyst was poisoned...". Adding
to the drawbacks of Schrock type catalysts is their thermal 'instability'. There are polymer
systems in which heating the reaction mixture would be advantageous toward achieving
maximum yields or molecular weights; however, Schrock's catalysts general decompose
over the temperature range of 60-80 °C. 20 So, although the introduction of Schrock's
catalysts opened up vast areas in metathesis and polymerization, there is still a great need
for new catalysts which are easier and less expensive to prepare.
1.3 Chelate Stabilized Alkylidenes
An intuitive approach to the synthesis of an alkylidene compound with a greater
thermal stability would be to use chelating ligands somewhere in the molecule. The use of
a chelating ligand may also produce interesting stereochemical properties in the metathesis
reactions. This approach has been investigated by Schrock, Grubbs, Boncella, VanKoten
and others. There are a number of options as to where to apply 'chelates' in these
complexes. Schrock has made a series of diolate complexes 21 of the type
Mo(CHCMe2Ph)(NAr)(diolate) Figure 1.9. Although no comment is made about
(R4tart)Mo(NAr)(CHMe 2 Ph)
R = phenyl, naphthyl
" siMe 2 Ph t-Bu' -SX- >B»
BTNO(SiMe2Ph) 2 Mo(NAr)(CHMe2Ph) Biphenol(t-Bu) 4 Mo(NAr)(CHMe2Ph)
Figure 1.9. Bidentate diolate complexes prepared by Schrock.
the thermal stability, it is assumed that they are more stable than the complexes with
monodentate alkoxides. These compounds do, however, allow for stereochemical control
of ROMP reactions. Grubbs has taken an interesting approach by synthesizing o-
substituted aryl alkylidenes 22 , where the o-substituent has o-donor properties and can
chelate to the metal center, stabilizing the alkylidene Figure 1.10.
VanKoten's alkylidenes are stabilized by chelating c-donors as well. 23 In the tungsten(VI)
alkylidene complex, W(NPh)(C6H4-o-CH 2 NMe2)(CHSiMe3)(OSiPh 3 ), the -NMe 2 group
on the orrto-methylene group acts as a a-donor, adding a chelate effect Figure 1.11.
THF'
OR' = OCCH 3 (CF 3 ) 2
R = H, Me, i-Pr
Figure 1.10. Grubbs' Catalyst
■NMe 2 SiMe 3
Figure 1.11. VanKoten's Catalyst.
Work done here at Florida by Blosch, Gamble, and Vaughan in the research group of
James Boncella 24 has focused on the use of the tris-chelating, mono-anionic ligand
hydro(tris)pyrazolylborate, Tp. Six-coordinate alkylidene complexes of the type
10
TpM(NAr)(CHR)(X) (M = W, Mo; R = CMe 3 , CMe 2 Ph; X = CI, Br, OTf, OMe, NHPh)
have been isolated Figure 1.12. These complexes show remarkable air and thermal
stability, although they only show metathesis activity in the presence of a Lewis acid,
which generates a vacant coordination site. Once again, the importance of coordinative
unsaturation is observed.
M = W; Mo
Y =NAr,0
X = CI; Br; OTf; OMe; NHPh
R =Me;Ph
Figure 1.12. Tridentate chelate complexes using the
hydro(tris)pyrazolylborate hgand.
The use of chelate ligands has provided two things to the chemistry of alkylidenes.
First, it has produced more thermally stable alkylidenes, even air-stable in the case of the
Tp alkylidenes. Secondly, the chelates ligands have greatly reduced the reactivity of the
alkylidenes towards olefins. The ultimate goal of this work would be to design a ligand
which provided stability while maintaining a high olefin affinity at the metal center.
Obviously this would mean a coordinatively unsaturated, electron deficient molecule. A
look back at the some of the known chelated alkylidene compounds reveals an undesirable
trend; the chelate ligand involves a neutral G-donor interaction. In simple terms, all this
does is clog the coordination sphere of the molecule. A more pragmatic approach would
eliminate neutral G-donor ligands to a great extent and concentrate on the use of anionic
ligands as chelates. The Tp ligand for example is a tridentate, mono-anionic ligand. Van
Koten's chelate could be considered a bidentate, mono-anionic hgand.
11
1.4 Polydentate. Polyanionic Chelate Ligands
An ideal ligand would be a polyanionic, polydentate ligand. Either a bidentate, di-
anionic ligand, or a tridentate, tri-anionic ligand. There are a number of examples in the
literature of multidentate, multi-anionic ligands. Schrock and Cummings have used a
tetradentate, tri-anionic ligand to prepare some novel high oxidation state titanium, 25
vanadium 25 and tantalum 26 compounds. The ligand, (Me3SiNCH2CH2)3N was used to
stabilize an interesting terminal phosphinidene complex as well as some other high
oxidation state early transition metal complexes Figure 1.13. Verkade 27 first used
methyl derivatives of this ligand, (MeNCH2CH2)3N, to stabilize some group (W) and (V)
compounds Figure 1.14. Gade 28 has used a similar ligand, H3CC(CH2NHR)3 (R =
Me, Et, i Pr, SiHMe2, and SiMe3), to stabilize titanium complexes. This ligand has a
carbon in the bridgehead position, avoiding the o-interaction which the nitrogen had with
the electrophilic metal center, creating a tridentate, tri-anionic ligand, thereby decreasing the
metal centers coordination number by one.
PR
Me 3 Si
N
Me 3 Si-l N /
Ta — .fj— - SiMe3
N-
5
t
Y
1— . Y
J- /
M = V, Ta
Y = 0, NMe
Z = 0, NR
igure 1.14. Gade's
tetradentate
tris-anionic ligands.
Figure 1.13. Phosphinidene
stabilized by Verkade's ligand.
Wilkinson 29 has employed the use of o-phenylene&arnine in the stabilization of
tungsten (V) and (VI) compounds. One negative aspect of this particular bidentate, di-
anionic ligand is the tendency for rearrangement of the bis-amide to an imido-amine. This
problem could be easily overcome by synthesizing N,N'-disubstituted derivatives. This
premise is where the present study begins. A number of novel N,N'-disubstituted
12
derivatives of o-phenylenediamine and 1,8-diaminonapthalene were synthesized and then-
application as bidentate, di-anionic ligands were investigated. All of the work reported here
involves tungsten (VI) phenylimido or oxo complexes exclusively. The high-yield
synthesis of various tungsten (VI) phenylimido ligand stabilized complexes allows a
convenient route into the reaction chemistry of these complexes. This work, involving the
preparation of starting materials, will be covered in Chapter 2. Simple alkylation reactions
allow the isolation in good yield of a series of mono- or di-alkyl complexes. Isolation of
stable ris-bisalkyl complexes offers a look into the reaction chemistry of these compounds,
and will be the focus of Chapter 3. Heating the bis neopentyl derivative in the presence of
PMe3 induces a-hydrogen abstraction, forming an alkylidene and one equivalent of
neopentane. The neopentylidene complex is an active catalyst for the ROMP of
norbornene. The activity of the catalyst can be tailored by the addition of excess ligand to
the reaction mixture. This will also be covered in Chapter 3. A majority of the chemistry
found in Chapters 2 and 3 has previously been published. 30 An interesting feature of the
alkyl complexes is that they react at room temperature with molecular hydrogen to form
high oxidation state hydride complexes. The addition of a a-donor ligand accelerates the
reaction tremendously as well as aides in the stabilization of the molecule. The seven-
coordinate dihydride species formed reacts with ethylene, hydrogenating one equivalent,
while the reduced metal species forms a tungsten (IV) ethylene complex. The reactivity of
the alkyls towards hydrogen and olefins will be the focus of Chapter 4.
CHAPTER 2
SYNTHESIS OF BIS-AMIDE CHELATE LIGANDS
AND LIGAND-METAL COMPLEXES
2.1: Preparation of Bidentate Ligands.
In order to pursue the use of 1,2-phenylenediarnine as a bidentate, di-anionic
ligand, an accessible route to the synthesis of bulky N,N'-disubstituted derivatives was
desired. A thorough review of the literature reveals surprisingly few examples of such
compounds. The only known bisalkyl example is N,N'-dimethyl-l,2-
phenylenediamine, 31 which is prepared through a tedious, dangerous, multi-step synthesis.
There are examples of other disubstituted derivatives such as -S(0)2tolyl (tosyl) 31 and
-C(0)Ph. 32 A slight discrepancy in the literature was discovered for the case of N,N'-
bis(trimethylsilyl)-l,2-phenylenediamine, l,2-(Me3SiNH)2C6H4, 1. Before this was
discovered, however, a nearly quantitative one-step synthesis of 1 was discovered eq
2.1. (9-phenylenediamine was dissolved in Et20 on as large a scale as available
Me 3 Si
f^Y NH2
1. 2eq. Me 3 SiCl
2. 2 eq. NEt 3
Et 2 0, °C
\
H
H
eq2.1
./
Me 3 Si
glassware would allow. A slight excess of two equivalents of Me3SiCl was added,
forming a white precipitate, presumably the hydrochloride salt. A slight excess of two
equivalents of NEt3 was added to the slurry. The solution became yellow amidst the solid.
Filtering and removing solvent gave a bright yellow solid in greater than 95% yield. It is
13
14
important to note that the slightest impurity causes formation of a yellow oil, partly due to
the low melting point (29 °C) of 1.
The preparation of 1 described above differs greatly from the literature methods.
Compound 1 was first reported in the literature in 1960 by Birkofer. 33 Birkofer refluxed
o-phenylenediamine, two equivalents of Me3SiCl and NEt3 in toluene followed by a
fractional distillation to give a moderate yield of 1. In 1970, West 34 reported refluxing o-
phenylenediamine, hexamethyldisilazane, and a catalytic amount of MesSiCl in THF for 24
hours. Fractional distillation using a spinning band column gave an 80% yield of 1. West
also reported that addition of MeLi to 1 in THF solvent caused rapid 1,4 anionic
rearrangements to occur. 34 This finding was an important consideration when solvents for
the ligation chemistry were chosen. In 1985, Lappert reported heating o-
phenylenediamine, Me3SiCl, and NEt3 in toluene (with no mention of Birkofer). 35
Lappert then treated 1 with MgBu2 to give the deprotonated dimer, [Mg{|i-
N(SiMe3)C6H4N(SiMe3)-o}(OEt2)]2- Maatta 36 reports another preparation in 1992.
Here, o-phenylenediarnine is deprotonated with two equivalents n-BuLi, followed by
addition of two equivalents of Me3SiCl. The product, 1, is isolated as a yellow oil by
vacuum distillation in 80% yield. One concern that this report brought out was that when
(Me3SiNH)2C6H4, 1, was allowed to react with WClg, two equivalents of HC1 and two
equivalents of Me3SiCl were lost, forming a bridging di-imide eq 2.2.
1. CH 2 C1 2 ™
2. THF Cl^N N^Cl
w w eq l.i
thf' £ ci a-^ THF
From Lappert's account, 1 should be susceptible to deprotonation. Addition of two
equivalents of n-BuLi to 1 afforded the white salt Li2(Me3SiN)2C6H4, 2. Interestingly,
the salt was soluble in C6D6 and the ! H NMR of 2 verifies that there were no N-H
15
protons. The salt, however, was extremely moisture sensitive and spontaneously ignited
upon exposure to air, hence prolonged storage was difficult. Before the application of 1
and/or 2 as a ligand will be addressed, the synthesis of other potential ligands will be
discussed.
Although the high yield synthesis discussed for 1 might seem applicable for a series
of silyl chlorides, it did not prove to be. However, when refluxing hexanes were used as
the solvent instead of Et20, a series of silylated compounds were isolated in high yield.
This general route applies to making the -SiMe2Ph, 3; -SiMePh2, 4; or -SiMe2-?-Bu, 5,
derivatives of o-phenylenediamine. Another derivative of o-phenylenediamine was
prepared in this manner, 4,5-dimethyl-l,2-(Me3SiNH)2C6H2, 6. This route was also
utilized to prepare l,8-(Me3SiNH)2CioH4, 7, in high yield and on a large scale from 1,8-
diaminonaphthalene and two equivalents of both Me3SiCl and NEt3. An asymmetric
disubstituted o-phenylenediamine derivative, l-(PhNH)-2-(Me3SiNH)C6H4, 8, was
synthesized similarly from N-phenyl-o-phenylenediamine, Me3SiCl and NEt3.
Attempts to synthesize dialkyl derivatives of o-phenylenediamine proved less
successful. In an attempt to synthesize l,2-( i PrNH)2C6H4, o-phenylenediamine was
slurried with excess sodium acetate in a cold acetic acid/acetone/water mixture. Excess
NaBH4 was added slowly. After neutralizing the solution with NaOH and isolation of
products, a 1:1 mixture of products was formed. They were separated by flash
chromatography and analyzed. l,2-0PrNH)2C6H4, 9, was isolated as a colorless oil. The
other product was a heterocyclic compound, 10, which is shown in eq 2.3. The
heterocycle most likely forms by an attack of one imine nitrogen on the other imine carbon,
followed by a 1,3 proton shift. Altering the reaction conditions did not change the relative
yields of 9 and 10. The *H NMR of 10 is shown in Figure 2.1. Since formation of the
7-membered heterocylce seemed unavoidable in this system, the same reaction was
attempted using 1,8-diaminonaphthalene. Here, the formation of a 6-membered
heterocycle might be less likely due to the strain involved in one imine attacking
16
NH,
NH,
1. acetic acid/H20
2. sodium acetate
3. acetone ^
N= CMe,
:CMe,
l.NaBH 4
2. NaOH
eq2.3
10
the other. A mixture was not observed. A 90% yield of a 6-member heterocycle, 11, was
the only compound isolated eq 2.4. This compound probably arises from attack of the
imine carbon on the lone pair of electrons from the nitrogen, followed by a 1 ,3 proton
shift. Changes in the reaction conditions did not afford any of the desired diamine.
NH,
NHo
1. acetic acid/H20
2. sodium acetate
3. acetone
4. NaBH 4
5. NaOH
eq2.4
11
2.2: Synthesis of New Ligand Metal Complexes.
Addition of these new ligands to metals was the next step in the project. Two
starting materials were initially chosen as trial compounds, WOCI4, which was readily
available, and W(NPh)Cl4(OEt2). W(NPh)CU(OEt2) can be prepared in high yield from
the addition of PhNCO to WOCI4, resulting in the loss of CO2. The ligand chosen for the
majority of the work reported was l,2-(Me3SiNH)2C6H4, 1. There are two simple routes
available for the addition of the ligand to the metal center. First, the ligand could be doubly
17
c
<
X X
^2 z^
^T
a*
x
^ -!
"o
o
B
o
J3
■p
<U>
l-<
O
o
o
e4
4)
u
a
\\ //
18
deprotonated and then added to the metal center in a simple metathesis reaction, forming the
ligand complex and two equivalents of a chloride salt. The other route would be to add the
diamine ligand directly to the metal, losing HC1 either spontaneously or through addition of
a base such as NEt3. The first route proved the more successful, and the second route was
attempted with minimal success.
An Et20 solution of WOCI4 was added to 2 at -78 °C. Work-up afforded a
moderate yield of WOCl2(Me3SiN)2C6H4, 13, eq 2.5. Studies of the reaction chemistry
of this compound were not undertaken since isolating pure 13 is extremely
Me3Si MesSi
eq2.5
difficult. Altering the reaction conditions did not alleviate this problem. Attempts are
currently underway to alter the starting W=0 complex and allow cleaner isolation of
products, thereby allowing a thorough study of the reactivity of 13 a .
In a similar reaction, W(NPh)CU(OEt2) was allowed to react with 2 at -78 °C,
which afforded W(NPh)Cl2(Me3SiN)2C6H4, 14, as an orange-red powder. The bis-
amido complex, 14, was also prepared on a large scale by deprotonating the diamine in
situ. This method proved the most successful in preparing 14 in high yield eq 2.6. With
an easy, large scale, high yield synthesis, 14 was an excellent starting point to investigate
the reactivity of these chelated complexes. The electron count of the tungsten is formally
considered to be 14 electrons, considering the imido as a 6 electron donor with the amide
bonds contributing 1 electron each to the total electron count. The electronic donation of
a William Vaughan has undertaken the synthesis of other W=0 complexes to be used as precursors for the
addition of the ligand, 1. These W=0 complexes have 'softer' substituents and would presumably be more
tolerant to metathesis.
19
the bidentate ligand is unclear, the nature of which could make the molecule a 14e-, 16e- or
18e- complex.
Me 3 Si
M
N
H
H
2 eq n-BuLi
Me 3 Si
Me 3 Si
N.
*T
Li
.Li
/
Me 3 Si
"- 2- in situ - 1
N
Clxll/Cl
+
cr
OEt 2
/ t x a
Me 3 Si
KLa
W e q2.6
Me 3 Si 14
X-ray quality crystals were obtained by dissolving 14 in toluene and cooling to -10
°C. The thermal ellipsoid plot of 14 is shown in Figure 2.2, while selected bond lengths
and angles are found in Table 2.1. The geometry of the molecule is square pyramidal
with the imido nitrogen in the axial position. The W atom lies .58 A above the plane
defined by the two amido nitrogens and the two chlorides. This is similar to the crystal
structure of W(NPh)Cl4(OEt2), which is octahedral with the imido cis to all four chlorides.
The imido nitrogen bond length is 1.730(10) A, which is well within the range of other
imido complexes where the imido group is considered to be a six electron donor because of
donation of the lone pair of electrons on the nitrogen to an empty d orbital on the metal
center. One feature of the structure of the molecule that is quite surprising is the
'orientation' of the ligand. The phenyl group of the bis-amide ligand is distorted and bent
toward the metal center. The dihedral angle between the plane of the C1-C6 ring and W,
Nl, N2 is only 130°, as if there were a metal-olefin type interaction between the W and the
phenyl ring of the ligand. The complement of this angle is referred to as the 'fold angle',
50 °, and is quite diagnostic when compared to other compounds. The interaction appears
quite significant; the distances between W and CI and W and C2 are only 2.58(1) A.
Although this is greater than the W-C bond length in high oxidation state tungsten alkyl
complexes, it is still within the vanderWaal's radii. In the few compounds that are known
with this type of ligand, the distances are much greater (>2.80 A). 29 > 3 7 There are only a
20
•d
CO
a
2
p
P<
o
<x 5
o 3
oH
3 o
s I
O "t3
co U
■S<H
•— H
I (
•a
3
(31!
21
few examples of structures of o-phenylenediamido-type ligands. 2 9,37,38 None of these
structures appear to have an interaction between the ring carbons and the metal center. If
the ring is in fact acting as a two electron donor, the electron count on the metal would now
be 16e-.
Table 2.1: Selected Bond Lengths (A) and Angles (°) for compound 14.
1-2 1-2-3
Cll
W
C12
2.383(4)
82.9(2)
C12
w
Nl
2.387(4)
150.5(3)
Nl
w
N2
1.951(11)
83.9(4)
N2
w
N3
1.952(11)
110.2(5)
N3
w
CI
1.730(10)
137.4(4)
CI
w
C2
2.582(13)
31.9(4)
C2
w
Cll
2.582(13)
117.2(3)
Nl
Sil
C13
1.768(10)
108.4(7)
N2
Si2
C16
1.781(12)
106.0(7)
CI
Nl
W
1.42(2)
98.8(7)
C2
N2
w
1.40(2)
99.4(8)
C7
N3
w
1.39(2)
166.2(9)
Analogies can be made to some other types of compounds where similar bonding
exists. Peterson 39 solved the crystal structure of a Cp2Zr chelated bis-amido complex in
which the distances between the (3-carbons and the zirconium are 2.612(3) A and 2.603(3)
A. Peterson claims that this close interaction is due to donation from the filled 7t-orbital of
the C=C bond to the empty d-p- orbital on the zirconium as shown in Figure 2.3.
Rothwell 40 observed similar results with quite similar bond lengths, in the 2.40-2.60 A
range, for other enediamido and enamidolate chelate compounds of zirconium, titanium and
tantalum as shown in Figure 2.4. These compounds, including 14, not only have close
contact distances, but also have abnormally large 'fold angles'. The compounds prepared
by Rothwell and Peterson have fold angles between 35 and 50 °. Rothwell also measured
the AG^'s for the barrier to 'flip' these enediamido metallacycle rings. The AG^'s were in
the 13-16 kcal/mol range. 40 This type of 'flip' would not be observed in a molecule such
22
as 14 since the molecule does not have a mirror plane through the metal center. Both
Rothwell and Peterson also point out the fact that although the M-Cp bond lengths are
longer than normal for similar M-R complexes, they are within the range of M-C bond
lengths in M-Cp complexes. Typically, W-Cp metal-carbon bond lengths are between
R
R
R'
I
A y» 0Ar
I— *~M
"*"* N N QAr R ' = *?• Ph ' tBu
M = Ti, Zr, Hf
R = CH 3 , CH 2 Ph
Figure 2.3:
A zirconacene enediamido complex.
R'
Figure 2.4:
Enediamido complexes of group 4 metals.
2.3 and 2.45 A. This is shorter than the 2.58 A observed for 14, and does not fit as well
with the comparisons suggested by Rothwell and Peterson. Lappert has observed similar
behavior for some bidentate, di-anionic oxylidene complexes of some bis-cyclopentadienyl
group 4 and 5 metals. 41 The metallacycles in these compounds also displayed a significant
interaction with the metal center, having fold angles between 41° and 53 °.
Continued investigation of the use of these chelating bis-amide ligands led to the
synthesis of other new compounds. There were two goals for preparing new derivatives of
these bis-amide derivatives, less solubility and more crystallizability. To this end, 1,2-
(Me2PhSiNH)2C6H4, 3, was deprotonated in situ and reacted with W(NPh)Cl4(OEt2) to
yield W(NPh)Cl2(Me2PhSiN)2C6H4, 15. This compound was somewhat less soluble but
recrystallization proved unfruitful. Yellow crystals of l,8-K2(Me3SiN)2CioH4, 16 or 1,8-
Li2(Me3SiN)2CioH4, 17 were isolated when l,8-(Me3SiNH)2CioH4, 7, was
deprotonated with two equivalents of KH or n-BuLi. These salts react readily with
W(NPh)Cl 4 (OEt 2 ) to give W(NPh)Cl2(Me 3 SiN)CioH4, 18, as a dark powder which was
markedly less soluble than 13, 14, or 15 eq 2.7. Nonetheless, a suitable solvent could
23
not be found for recrystallization. The same reaction using 4,5-dimethyl-l,2-
(Me3SiNH)2C6H 2 , 6, yielded W(NPh)Cl 2 [4,5-Me2-l,2-(Me3SiN) 2 C 6 H2], 19. This
Me 3 Si
'K
Me 3 Si
Me 3 Si
=\ 1
N
N N II ,.** C1
-<:
Cl
Me3Si
18
eq2.7
complex certainly simplified the *H NMR spectrum, but did not show any greater ease in
isolation or crystallization. Attempts were made at synthesizing tungsten phenyl imido
derivatives using the other ligands mentioned; however, although results were
encouraging, full characterization of these derivatives was not obtained.
It was also possible to substitute the chloride atoms in 14 with a more labile
substituent. This was desirable if alkylation of the dichloride proved unsuccessful. When
14 was allowed to react with two equivalents of AgOTf, the bistriflate complex,
W(NPh)(OTf)2[(Me 3 SiN)2C6H4](OEt2), 20, was isolated as a bright orange powder.
This complex must be more electron deficient than 14 since it forms an etherate complex,
whereas 14 does not.
Since all these compounds are five-coordinate, electron deficient molecules, they
would be expected to form adducts with c-donor ligands. When PMe3 was added to a red
Et 2 solution of 14, the solution immediately turned purple. Addition of pentane followed
by slowly cooling the sample to -10 °C yielded dark purple crystals of
W(NPh)Cl2(PMe3)[l,2-(Me3SiN) 2 C 6 H4], 21. Integration of the !H NMR and
combustion analysis confirmed the stoichiometry of 21. Although 21 appears as a discreet
mono-adduct, the 31 P NMR spectrum shows a very broad singlet for the PMe3 ligand,
nearly 250 Hz wide, and suggests that at room temperature an equilibrium between 21 and
free PMe3 was established. More evidence will be given for this ligand exchange later.
24
Purple, crystalline G-adduct complexes were also formed when 14 was exposed to THF,
22; 3-picoline, 23; or CH3CN, 24, eq 2.9. Addition of these a-donors increases the
+ L
Me 3 Si
eq2.9
L = PMe 3 , 21; THF, 22; 3-picoline, 23; CH3CN, 24
formal electron count of the molecules to 16e- with no 7t-donation from the folding of the
ligand at this point. The donation of this electron density, as well as now having a 6-
coordinate complex, would clearly have an impact on the ligand 'folding' which was
observed in the structure of 14. Recrystallization of the PMe3 adduct, 21, by slowly
cooling a pentane solution to -10 °C gave purple, x-ray quality crystals.
The structure of 21, shown in Figure 2.9, has some unique features. Selected
bond lengths and angles for the structure of 21 can be found in Table 2.2. The PMe3
adds to the molecule trans to imido nitrogen, creating an octahedral geometry, with the
amido nitrogens and the chlorides mutually cis in the basal plane. In a comparison between
the structures of 14 and 21, one very general thing that stands out. Because of the added
electron density and steric bulk of the PMe3, all the bonds to the metal center are longer in
21. For instance, even the chlorides are 0.06 A or more further away. Most significandy,
the fold angle has increased from 50 ° to only 28 °. The W-Qing distances have increased
from 2.58 A each in 14 to 2.79 and 2.78 A in 21. It is interesting to note that the
geometry around the nitrogen atoms in the bis-amide ligands in both 14 and 21 is virtually
planar. The amide bond lengths in 21 are only slightly longer, 2.010(5) A and 1.990(5) A
than in 14, 1.951(1 1) A and 1.952(1 1) A. One feature of this structure which is quite
25
Table 2.2: Selected Bond Lengths (A) and Angles (°) for compound 21.
1-2 \-2
Cll
W
C12
2.449(2)
92.43(7)
Cll
w
P
75.86(7)
C12
w
P
2.443(2)
75.70(7)
P
w
Nl
2.720(2)
87.2(2)
P
w
N2
89.2(2)
P
w
N3
160.3(2)
Nl
w
N2
2.010(5)
80.8(2)
N2
w
N3
1.990(5)
105.8(3)
N3
w
CI
1.747(6)
124.6(2)
CI
w
C2
2.797(6)
29.7(2)
C2
w
Cll
2.785(6)
137.4(2)
Nl
Sil
1.781(6)
CI
Nl
W
1.402(8)
108.8(4)
C2
N2
W
1.387(9)
109.8(5)
C7
N3
W
1.388(9)
164.3(5)
unusual is the extremely long W-P bond length, 2.720(2) A. This bond appears to be at
least 0.2 A longer than most W-P bond lengths in W(VI) complexes. This weak
interaction is supported by the afore mentioned broad singlet observed in the 31 P NMR
spectrum. This long bond length may be due to trans influence of the imido nitrogen,
which is a strong trans influencing ligand.
A number of interesting new W(VI) imido and oxo complexes have now been
prepared. These new complexes have interesting structural characteristics which will play
an important role in influencing the chemistry associated with them.
26
g
I
O
1-1
P— \
Si
Si
P-i w
9 p<
cv£
•a c
P,.>>
£3 to
o
•a
a
u
CHAPTER 3
SYNTHESIS AND REACTIVITY OF W(VI) ALKYLS AND ALKYLIDENES
3.1: Background Information on WP/D Alkyls and Alkvlidenes.
In order to pursue the project goal of creating a new olefin metathesis catalyst,
alkylation of the W(VI) dichloride was investigated. There are surprisingly few examples
of group(VI) (fi alkyl complexes in the literature. 1 ' 2 - 42 ' 43 There are numerous examples of
cfi group (IV) alkyl and dialkyl complexes, most of which are used as Ziegler-Naatta type
catalysts. Homoleptic alkyls, such as WMe6 are well-known. 42 Other alkyls are less
prevalent. Schrock has isolated a number of W(VI) imido alkyl complexes. 44 Many of
these were isolated in attempts to find precursors for alkylidene complexes. It was
observed that W(NPh)Cl2(CH2CMe3)2 was not isolable. However, if one or two of the
chlorides are substituted with t-butoxide ligands, dialkyls can be isolated, W(NPh)Cl(0-f-
Bu)(CH 2 CMe3)2 and W(NPh)(0-t-Bu) 2 (CH 2 CMe3)2. In these compounds, the alkyl
groups are oriented cis to one another in a trigonal bipyramidal geometry. There are also
examples in which the alkyl groups are trans to one another. Schrauzer prepared a variety
of W(VI) dioxo complexes 45 of the type W(0)2R2(bipy), where R = Me, Et, n-Pr, and
CH2CMe3. These compounds are quite stable due to the chelate effect of the bipyridine
ligand, which also serves to lock' the alkyls trans to one another, limiting reductive
elimination or a-hydrogen abstraction reactions. The bonding in d° alkyl complexes is
rather straight-forward. The alkyl ligand acts as a 2e- donor ligand forming a G-bond with
the metal center. The most common means of preparing alkyl compounds is by simple
metathetical exchange reactions. 42 Grignard reagents and lithium, zinc, or aluminum alkyls
are commonly used as alkylating agents.
27
28
There are many possible reactions that can take place when a d° metal is alkylated,
prohibiting isolation of a transition metal alkyl complex. If the alkyl group has (3-protons,
the metal can undergo a (3-hydrogen elimination reaction. 2 ' 42 Another reaction that takes
place, especially with bulky alkyl groups, is a-hydrogen abstraction. 2 An alkylidene is
formed as a result. There are two mechanisms proposed for this reaction, neither of which
has been proven. One is initial a-elimination to form an alkylidene-hydride complex.
Evidence for this mechanism comes from the chemistry of later transition metals. This
addition is not possible for a cP metal center because the reaction involves oxidation of the
metal center. The other mechanism proposes a three-center, two-electron transition state
which eliminates alkane, forming the alkylidene. Both cc-abstraction mechanisms can be
seen in Figure 3.1. Since the discovery of the first alkylidene complex, other routes have
been discovered for preparing alkylidenes. 46
CH 2 R CHR CHR
I ll/ H II
M CH 2 R *- M ^ M +RCH3 (1)
CH 2 R
CH 2 R
H
R-C— --H , C ,HR
/
^_CH 2 R M -f-K M +RCH 3 (2)
R H
Figure 3.1. The two a-abstraction mechanisms for alkylidene formation.
Despite these developments, a-abstraction reactions are still the most common
method for preparing alkylidene complexes. Neopentylidene (=CHCMe3) and
neophylidene (=CHCMe2Ph) complexes are the most prevalent, due to their steric bulk and
lack of (3-protons. Reactions that proceed through a-abstraction can be divided into two
general categories, proximal a-abstraction and ligand induced a-abstraction a . Proximal a-
a Proximal a-abstraction and ligand induced a-abstraction are not commonly used in the literature, however
coining these terms is useful for the discussion.
29
abstraction refers to reactions in which an alkylidene is formed by oc-abstraction
immediately upon alkylation. This type of reaction was observed for the addition of excess
neopentyl grignard to TaCls, forming Ta(CHCMe3)(CH2CMe3)3. 13 The mere steric bulk
of the neopentyl groups induces a-abstraction, eliminating neopentane. The second type of
reaction, ligand induced a-abstraction, is characterized by the addition of a o-donor ligand,
most commonly PMe3, to a cis bis-alkyl complex, inducing a-abstraction and elimination
of an alkane. A classical example is the addition of PMe3 to
W(NPh)(CH2CMe3)2(PMe3)Cl2, which results in the formation of the alkylidene complex
W(NPh)(CHCMe3)(PMe3)2Cl2 and neopentane. 44 These principles will be discussed as
they apply to the synthesis of the new alkylidene complexes that were synthesized during
this study.
3.2: Synthesis of WCVD Bis-Alkvl Complexes.
Most of the reaction chemistry was performed on compound 14, since it was the
first compound isolated and was available in large quantities. When 14 was allowed to
react with two equivalents of ClMgCH2CMe3 in Et20 at -78 °C, the bis-alkyl complex
W(NPh)(CH2CMe3)2[(Me3SiN) 2 C6H4], 25, was isolated as a dark red crystalline solid
eq 3.1. The yield for this reaction was usually about 75-80%, and seems only to be
P
Me 3 Si T Me 3 Si
x N x N
V-VlU Et 2 rfWUv
W^ + 2 eq. ClMgCH 2 CMe 3 ^ > (| I .W eq 3. 1
1 1, /
Me 3 Si 14 Me 3 Si 25
limited by the extreme solubility of 25 in hydrocarbon solvents. There are many
interesting characteristics of this compound. The l R NMR, shown in Figure 3.2,
30
showed that there was a plane of symmetry in the molecule. The neopentyl methyl groups
were equivalent as were the -SiMe3 methyls. The methylene protons were observed as
diastereotopic protons at 2.13 ppm and 2.29 ppm. The 2 Jh-H was 10 Hz, while there were
183 W satellites observed at 1 1 Hz from 2 J\y-H- The aromatic region also shows the ligands
protons resonating in an AA'BB' spin system, stemming from the symmetry plane in the
molecule. These observations are consistent with the square pyramidal structure drawn in
eq 3.1 for 25. Since 25 is only a 14e- complex (the degree of interaction of the metal
center with the phenyl ring of the bis-amide ligand is not known, so an electron count of
16e- might also be possible), and coordinatively unsaturated, an agostic interaction of one
of the neopentyl methylene protons and the metal center is conceivable. It has been
established that the magnitude of the coupling of the methylene proton with the methylene
carbon is diagnostic of an agostic interaction. If the coupling constant is less than 120 Hz,
then an agostic interaction is likely. 47 The 1 Jq-U f° r 25 was 123 Hz, and is consistent
with a "normal" metal alkyl o-bond. An interesting point is that 25 was isolable as a cis
(bis)-neopentyl complex. Recalling the structure of 14, the steric crowding around the
metal center is overwhelming. It would seem likely that the bis-neopentyl complex would
undergo a proximal a-hydrogen abstraction upon alkylation. The chelation of the bis-
amido ligand may hinder the a-abstraction since rearrangement to a tetrahedral, four-
coordinate alkylidene is necessary.
Other bis alkyl complexes can be prepared in an analogous manner. The neophyl
derivative W(NPh)(CH2CMe2Ph)2[(Me 3 SiN) 2 C6H4], 26, was isolated in 85% yield as a
brownish powder which is less soluble in hydrocarbons than compound 25. For the case
of the dimethyl derivative, W(NPh)(CH3)2[(Me3SiN)2C6H4], 27, isolation was more
difficult. The compound was extremely soluble in pentane, and could only be isolated by
cooling a concentrated solution of 27 in Et20 (1.2 grams in 2 ml) to -78° C, which gave a
red solid after several days. The *H NMR spectrum of 27 is shown in Figure 3.3 and
clearly shows the 3:1 ratio of -SiMe3 to W-Me2 peaks. Coupling of 183\y to the methyl
31
2
a
a
w
o
_cu
OJ
in
.01
o
in
d
~^>
— ■*
^
10
U
c4
en
3
32
protons was also observed and gives rise to the satellites of the methyl peak with 2 Jw-H = 6
Hz. The ^C-H for 27 was 123 Hz as well, indicating that an agostic interaction is
unlikely. When 14 was treated with two equivalents of CIMgEt, a red oil was isolated.
The red oil appeared by NMR to be pure W(NPh)(CH 2 CH3)2[(Me3SiN) 2 C6H4], 28. The
*H NMR spectrum revealed methylene resonances as multiplets at 1.91 and 2.31 ppm,
while the ethyl-CH3 protons resonated as a singlet at 1.86 ppm. The ^c-H for 28 was 120
Hz, consistent with the other bis-alkyls isolated. It was interesting that an electron deficient
bis-alkyl complex with (3-protons was isolated. Often times these types of alkyls
decompose by (3-hydrogen elimination making them difficult to isolate. The dibenzyl
complex, W(NPh)(CH 2 Ph)2[(Me3SiN)2C6H4], 29, was prepared using benzyl grignard
as the alkylating agent. The *H NMR was interesting because the benzyl methylene
protons did not appear to be diastereotopic, as were the methylene protons in 25, 26 and
28. The methylene protons resonated as a singlet at 2.78 ppm and integrate 2:9 to the
-SiMe3 peak. However, when 29 was heated to 80 °C in C-jT>%, the resonance becomes
what appeared to be a triplet. Cooling the sample only broadened the singlet. The
methylene protons are considered diastereotopic, yet coincidentally have identical chemical
shifts, obscuring any coupling.
The synthesis of other bis-alkyl complexes has been investigated and show
promise, although most of the products have not been completely characterized. Reacting
two equivalents of allyl magnesium chloride with 14 gave a mixture of compounds. It
appeared as though the major product was a bis-allyl complex where one allyl group was
bound in an ri 1 manner while the other was T] 3 . More characterization is necessary to
determine the identity of the compounds. The substitution of the chlorides on 14 with aryl
groups was also investigated. A bright red powder was isolated when 14 is allowed to
react with two equivalents of PhLi. The l H NMR confirmed the identity of the compound
as W(NPh)Ph2[(Me3SiN)2C6H4], 30. This chemistry is currently being investigated by
other members of the Boncella research group. Since the reactivity of 14 has shown so
33
.2 Z
o t
34
much promise, alkylation of other dichloride derivatives was investigated. Allowing
W(0)Cl2[(Me3SiN)2C6H4], 13, to react with two equivalents of neopentyl grignard does
not afford isolation of the bis-neopentyl complex as expected. However, the l H NMR
spectrum of the brown solid shows resonances similar to the diastereotopic methylene
protons of 25. This result was not unexpected since the chemistry of the oxo complex was
consistently less clean than the imido compounds. A similar result was observed when
W(NPh)Cl2(Me3SiN)2CioH4, 18, was allowed to react with neopentyl grignard. Full
characterization was not achieved but the spectral data were consistent with a bis-neopentyl
complex. Better results were achieved when W(NPh)Cl2(Me2PhSiN)2C6H4, 15, and
W(NPh)Cl2[4,5-Me2-l,2-(Me3SiN)2C6H2], 19, were allowed to react with neopentyl
grignard. The two new bis-neopentyl complexes,
W(NPh)(CH2CMe3)2(Me2PhSiN) 2 C6H4, 31 and W(NPh)(CH 2 CMe3)2[4,5-Me2-l,2-
(Me3SiN)2CgH2]» 32, were isolated as dark red solids and have spectral properties that are
similar to 25.
Heretofore, only bis-alkyl or bis-aryl compounds were isolated. However, adding
only one equivalent of alkyl to the metal center should also be possible. When one
equivalent of neopentyl grignard was allowed to react with 14, the mono-neopentyl
chloride complex W(NPh)Cl(CH2CMe3)(Me 3 SiN)2C6H4, 33 was isolated as a red
powder eq 3.2. The methylene protons of the neopentyl groups were observed as
Me 3 Si
x N
\ La
W + 1 eq. ClMgCH 2 CMe 3
. / X n -78 °C \^ / \ ri eq3.2
N CI
Me 3 Si 14
diastereotopic doublets at 1.93 and 2.08 ppm respectively ( 2 Jh-H = 10 Hz). The ] H NMR
spectrum of the mono-neopentyl complex, 33, differs from the bis-alkyls due to the
35
absence of a plane of symmetry. The -SiMe3 resonances were observed as inequivalent
singlets, whereas they were equivalent in the bis alkyl complexes. In the aryl region, an
AA'BB' spin system was no longer observed for the bis-amide ligand, each ligand aryl
proton was inequivalent (two doublets and two triplets).
There are few examples of mixed alkyl complexes, so 33 would be a prime
candidate to allow asymmetric substitution. When 33 was allowed to react with one
equivalent of MeLi in an NMR tube, W(NPh)(CH 3 )(CH2CMe 3 )(Me3SiN)2C6H4 was
generated. The *H NMR showed four singlets in the alkyl region, in a 3:3:3: 1 ratio,
corresponding to the two-SiMe3 groups, the neopentyl group, and the methyl group.
Diastereotopic methylene protons are also observed. This compound was not isolated on a
preparatory scale. Another asymmetric compound was isolated when 33 was allowed to
react with one equivalent of LiNMe2, forming
W(NPh)(CH 2 CMe3)(NMe2)(Me3SiN)2C 6 H 4 , 34, eq 3.3.
N
Me 3 Si
W
N
Me3Si 33
a
+ LiNMe2
Me 3 Si
XT N /
w
N
/
Me 3 Si
34
N-
I
Me
eq3.3
The *H NMR spectrum of 34 reveals diastereotopic methylene protons as doublets at 1.33
and 2.60 ppm respectively. There is lack of rotation about the W-NMe 2 bond, since two
singlets were observed at 3.19 and 3.68 ppm. This lack of rotation is due to the n-
donation of the lone pair of electrons on the amide nitrogen to the metal center. This type
of interaction is quite common in electron deficient molecules such as 34. Taking into
account the electronic donation from the bis-amide ligand, this molecule should be
considered as being electronically saturated.
36
3.3: Alkylidene Formation From Bis-Alkvl Complexes.
In Section 3.1, the two mechanisms of alkylidene formation from bis-alkyl
complexes were discussed. The fact that bis-alkyl complexes were isolated does not
eliminate proximal a-abstraction as a route to alkylidene formation. Without adding a o-
donor ligand, a-abstraction could be thermally induced. Although there are no examples of
thermally induced a-abstraction reactions, this route should be viable. Many proximal a-
abstraction reactions are performed at reduced temperatures, and warmed to room
temperatures where a-abstraction takes place. Since the bis-alkyl complexes are thought to
exist at low temperatures in these reactions, a-abstraction occurs at or near room
temperature. Heating a C^De solution of 25 in a sealed NMR tube gave a very interesting
result. Neopentane formation was observed in the l H NMR, however, it was not a result
of a-hydrogen abstraction. The *H NMR spectrum reveals what appears to be a
metallacyclobutane complex formed from the y-abstraction of a proton from a neopentyl
methyl group eq. 3.4. The 2 H NMR spectrum of the p\p*-dimethylmetallacyclobutane
complex, W(NPh)(CH2CMe2CH2)(Me 3 SiN)2C6H4, 35, is consistent with other
3
Me 3 Si^ T Me 3 Si
/yvJ/-4 80 o C rrVVJV*
KJ^^ \ / 2-3 days
Me 3 Si 25
f
+ CMe 4 eq3.4
metallacyclobutane complexes in the literature. 48 There are two doublets, at -1.7 and 2.1
ppm respectively ( 2 Jh-H = 9 Hz), corresponding to the methylene protons of the
metallacycle. The large difference in chemical shift of the protons is consistent with other
metallacycles. 48 The methyl protons of the metallacycle resonated at 0.54 and 0.57 ppm
respectively. They were inequivalent since they lie above and below the plane of the
37
metallacycle. This compound has not been fully characterized since it was difficult to
isolate and purify. The difficulty in isolating the metallacycle results from the 2-3 days of
heating which were required for the complete thermolysis of 25 to 35. During this time,
metallacycle formed earlier in the reaction started to decompose to unidentifiable products.
However, 35 is formed by other routes and will be discussed at length later in Chapter
Four. It seems unusual that 25 would undergo a y-abstraction, however there are
examples of this type of reaction in the literature. For example, Marks 49 thermally
decomposes Cp*2Th(CH 2 CMe3)2 and observes the loss of neopentane, giving the p,(3'-
dimethylcyclobutane thorium complex, Cp*2Th(CH2C(Me)2CH2).
Further investigation into this reaction using other bis-alkyls proved to be
unfruitful. The bis-neophyl complex, 26, was interesting since it possesses at least three
thermal decomposition routes that involve proton abstraction reactions. These include: a-
hydrogen abstraction, forming a neophylidene; y-abstraction similar to 25 to give a |3-
methyl, fi'-phenyl metallacyclobutane; or orr/zo-metallation, forming a five-membered
metallacycle. Examples of each of these types of reactions have been reported in the
literature. The a-abstraction and y-abstraction reactions have already been discussed.
Orthometallation reactions are observed for compounds in which the abstraction of a proton
from the ortho position of an aryl group forms a five-membered ring. 2 - 50 A good example
is the thermolysis of CH 3 Rh(PPh 3 )3, shown in Figure 3.4, in which the ortho proton of
Ph
[(C 6 H 5 )P] 3 RhCH
\
p,^ P. ,Rh[P(C 6 H 5 )3] 2
-CH 4
Figure 3.4. Orthometallation of (Ph3P)3RhMe
one of the phenyl groups is abstracted, releasing methane and forming a metallacycle. 51
However, when 26 was thermally decomposed at 90 °C for 3 days, no discernible
products were observed. Interestingly, the P-methyl, p'-phenyl-metallacyclobutane
38
complex will be isolated and discussed by an alternate route in Chapter 4. Similarly, only
complete decomposition to indiscernible products was observed when the dibenzyl and
diethyl compounds were heated. The dimethyl complex was unique in that it was thermally
stable over a period of 10 days at 90 °C.
Since no thermal pathways seemed to lead to alkylidene formation, ligand-induced
a-abstraction was attempted. In a sealable NMR tube, one equivalent of PMe3 was added
to a C<5D6 solution of the bis-neopentyl complex, 25. Over a period of ten days at room
temperature, no reaction was observed by *H NMR. Interestingly enough, no peak shifts
were observed corresponding to coordination of PMe3. Even upon cooling a C7D8
solution of 25 and PMe3 gives no evidence of ligand coordination by observation of the l H
NMR. This behavior was contradictory to the behavior of the dichloride precursor, 14,
which forms adducts with o-donors quite readily. The bis-neopentyl complex, 25, is
isoelectronic with 14, but the steric environment at the metal center in 25 would obviously
be much more hindered. The tube was then warmed to 70 °C in an oil bath. After only
three hours, neopentane formation was observed by *H NMR. Additionally, a doublet
began to grow in at 9.62 ppm, indicative of an alkylidene proton coupled to a bound
phosphine. The reaction proceeded nearly to completion at this temperature in 3 days;
however, it was found that the reaction proceeds faster and much cleaner with two or three
equivalents of phosphine present and a temperature of ca. 90 °C, eq 3.5.
Me 3 Si x I Me 3 Si H x ^X
, N \ N PMe 3
Me 3 Si 25 Me3S / 36
In order to prepare and characterize this new alkylidene on a preparatory scale, a problem
had to be overcome. In an open system, PMe 3 , which has a high vapor pressure and boils
39
at 39 °C, would be lost when the reaction was heated to 90 °C. Additionally, heating a
solution in a closed system using conventional Schlenkware would be dangerous due to a
possible buildup of pressure. This problem was overcome by dissolving 25 in toluene in a
tube fitted with a Young's joint with a Teflon seal. Three equivalents of PMe3 were added
and the reaction was heated to 90 °C for 12 hours. The color of the solution changed from
dark green to bright orange over the time of the reaction. After cooling to room
temperature, the solution was transferred to a Schlenk flask where the solvent was
removed. Extracting with pentane and cooling to -10 ° C gave orange crystals of the new
alkylidene complex, W(NPh)(CHCMe3)(PMe3)[(Me 3 SiN)2C6H4], 36.
In the ! H NMR of 36, a doublet was observed at 9.62 ppm ( 3 J P . H = 4 Hz)
corresponding to the alkylidene proton. Tungsten satellites were also observed for this
resonance ( 2 Jw-H = 1 1 Hz). The alkylidene carbon was observed at 277.4 ppm ( l Jc-Ha =
1 10 Hz). This coupling is consistent with an agostic interaction between the alkylidene
proton and the metal center. The PMe3 resonance was observed as a doublet at 0.98 ppm
( ! Jp-H = 9 Hz) in the *H NMR spectrum. There are three other singlets in the alkyl region
of the 2 H NMR spectrum of 36, all in a 1: 1 : 1 ratio. One is the neopentyl methyl group,
1.39 ppm, while the other two are the silyl methyl groups, 0.38 and 0.41 ppm. The
aromatic region also confirms that the molecule no longer has a plane of symmetry which
would make the silyl methyls equivalent.
The geometry of the five-coordinate alkylidene complex, 36, cannot be deduced
merely from the spectroscopic data. Since this was a five-coordinate complex, there were
numerous square pyramidal and trigonal bipyramidal complexes which would have fit the
spectral data. Therefore determination of the crystallographic structure was essential, not
only to determine the geometry of the molecule, but also to gain insight into the catalytic
activity of the molecule which will be discussed later in this chapter. Slowly cooling a
pentane solution of 36 to -10 °C afforded single orange crystals which were suitable for
diffraction.
40
The thermal ellipsoid plot of 36 is shown in Figure 3.5. Selected bond lengths
and angles can be found in Table 3.1. Upon examining other group (VI) alkylidene
complexes, 8 it was found that the structure of 36 was very unique. The geometry was
square planar with the alkylidene in the apical position. The tungsten atom lies 0.61 A
above the square plane defined by the imido nitrogen, the PMe3 phosphorous atom, and the
two amide nitrogens. The average deviation of Nl, N2, N3, and PI from the square plane
was only 0.03 A. Re-examining the issue of the interaction between metal center and the
7t-system of the bis-amide ligand gives an expected result. Since the electron count of the
molecule has been increased by two by the addition of the ligand, a decrease in the fold-
angle would be expected. The fold angle was 40 °, a 10 ° increase from the dichloride
structure, 14, yet 12 ° less than the fold angle in the six-coordinate PMe3 adduct of the
dichloride, 21. The 40 ° fold angle suggests a weak interaction between the aryl ring of the
bis-amide ligand and the metal center. The angle may be due, in part, to the great steric
bulk around the metal center. Thus, the folding of the bis-amide ligand may be necessary
to relieve steric interactions.
It was apparent that the chelating nature of the ligand has dictated the observed
geometry of the molecule. The literature reveals that five-coordinate imido-alkylidene
complexes of tungsten and molybdenum prefer to adopt trigonal bipyramidal, rather than
square pyramidal structures. The compounds, ann'-W(fra«.y-CHCH=CHMe)[N-2,6-
C6H 3 e'Pr)2](OCMe(CF3) 2 ]2(quinuclidine) 52 and W(CHCH=CHPh 2 )[N-2,6-
C6H 3 ('Pr)2](OCMe(CF3)2]2[P(OMe)3]53 are good examples of the preferred trigonal
bipyramidal structure of these types of compounds Figure 3.6. Although 36 and these
two alkylidenes have similar substituents, the geometry's are much different. The
geometric constraints of the chelating bis-amide ligand must be responsible for the
41
c
o
ft
H
42
Table 3.1: Bond Lengths (A) and Angles (°) for the non-H atoms of compound 36.
1-2 1-2-3
P1 W Nl 2.502(4) 82.8(4)
PI W N2 148.13
PI W N3 81.2(3
Nl W N2 1.789(9) 98.4(4)
Nl W N3 140.14
Nl W C13 103.6(5
N2 W N3 2.095(10) 77.8(4)
N2 W C13 H3.0(5)
N3 W C13 2.067(10) 114.6(4)
N2 Si2 C18 1.736(11) 108.6(6)
N3 Si3 C21 1.761(9) 111.8(6)
C1 Nl W 1.387(14) 160.8(9)
C7 N2 W 1.39(2) 106.6(8)
W N2 Si2 129.8(5)
C12 N3 W 1.40(2) 105.6(7)
C8 C7 N2 128.613)
C12 C7 N2 1.43(2) 114.6(11)
C14 C13 W 1.50(2) 148.4(9)
C13 W PI 1.884(13) 97.5(4)
unique geometry of 36. The bis-amide ligand of 36 should be able to coordinate in a axial-
equatorial ligation, allowing the molecule to adopt a trigonal bipyramidal geometry, but it is
not observed.
T N
"Pr '
RO'
Pr 1 t* ss v- Pl ' i
>=< >Pr N ^; »
Ph /
RO
P(OMe) 3
>h Me
Figure 3.6. Examples of trigonal bipyramidal alkylidenes.
Although the solid state structure of the compound has been solved, the structure in
solution was actually the key to the reactivity of the molecule. When the alkylidene proton
was irradiated in an nOe experiment, a 6% enhancement was observed for both the silyl
43
methyl groups. No significant enhancement was observed for the imido aryl protons, or
the PMe3 methyls. When the neopentyl methyls were irradiated, the ortho-aryftrmdo
protons and the PMe3 protons where enhanced by 2.5% and 3.7% respectively, while no
significant enhancement was observed for the silyl methyl groups. This geometry will be
referred to as syn, where the neopentylidene r-butyl group is syn to the imido group.
There are two reactions which should be considered at this time to better understand
the role of the PMe3 in the formation of the alkylidene. First when Cu(I)Cl was added to a
C6D6 solution of the alkylidene, 36, formation of the metallacyclobutane complex, 35,
was observed by ! H NMR eq 3.6. Cu(I)Cl forms an insoluble adduct with PMe3 and
effectively removes it from the solution. The four-coordinate alkylidene then undergoes a
rearrangement to the metallacycle. The rearrangement is effectively a 1,3 shift of a proton
^ Jf*. II ^^^ \ T N
^/^ +Cu(I)C1 ^^ (J N /\A +CuC1(PMe3) * eq36
M63Si/ 36 Me 3 Si /N 35
from a y-methyl to the alkyhdene carbon, as well as forming the new W-C bond. Although
the nature of this rearrangement is not known, the result is undeniable and will be
discussed further in Chapter 4. Secondly, when PMe3 was added to a CgDg solution of the
metallacycle, 35, complete conversion to the alkylidene, 36, was observed by !H NMR
eq 3.7. These two reactions show the relationship between the alkylidene, 36, and the
metallacycle, 35.
Insight into the mechanism by which the alkylidene, 36, is formed from the bis-
neopentyl complex, 25, eq 3.5, is gained by these reactions. The thermolysis of 25 in
the absence of PMe3 might initially give a four-coordinate alkylidene, which quickly
rearranges to give the five-coordinate metallacycle, 35. In the presence of PMe3, the four-
coordinate alkylidene is 'trapped' by the phosphine, forming 36. The intermediate four-
44
Me 3 Si
N.
N
VJI/^
w;
N
X
Me 3 Si
./
35
+ PMe 3
C 6 D 6
Me 3 S
\ H v^
N,.
N PMe 3
Me 3 Si 36
eq3.7
coordinate alkylidene could be tetrahedral, and coordination of the PMe3 would result in
rearrangement to the observed geometry of 36, with the alkylidene in the apical position.
This mechanism can be seen in Figure 3.7. Regardless of the actual mechanism, the
observed net result was still a-abstraction induced by PMe3.
P
Si. T
Me 3 Si 25
<■
Me 3 Si
W-
<^n'
Me 3 S
3 M
H
Me3Si
PMe 3
Me 3 S
/ \
PMe 3
/
Me 3 Si
36
Figure 3.7. Scheme for alkylidene and metaUacycle formation
showing an intermediate tetrahedral alkylidene.
Although the application of the PMe3 ligand to induce an a-abstraction reaction
might be widely applied to the other bis-alkyl compounds isolated, the bis-neopentyl
appears to be a unique case. The neophylidene compound can be isolated, however, a
45
longer reaction time is necessary. When the dimethyl complex, 27, was heated to 90 °C in
the presence of excess PMe3, no reaction was observed over 10 days, not even
decompostion of the dimethyl complex. Once again, it was astonishing that no PMe3
adduct formation was observed. Adduct formation would be expected since the methyl
substituents are not much bigger than the chlorides in 14. When the diethyl complex, 28,
was heated to 90 ° C with PMe3, decomposition to indistinguishable products was
observed. Surprisingly, when the dibenzyl complex, 29, was heated with excess PMe3
the compound appeared quite stable. No benzylidene formation was observed over time in
the l H NMR, although after a week at 90 °C, decomposition occurred. Though
disheartening, it is not uncommon to see a unique behavior when dealing with neopentyl
and neophyl compounds. The first as well as the most common examples of alkylidenes
are either neopentyl or neophyl.
The nature of the a-donor ligand necessary to induce a-abstraction was also
investigated. It would be advantageous to be able to prepare alkylidenes from the bis-
neopentyl compound using the weakest a-donors available. This would facilitate easy
removal of them either to isolate a four-coordinate alkylidene or the in situ dissociation of
the ligand forming a transient four-coordinate intermediate. When the bis-neopentyl
complex, 25, was heated in the presence of PEt3 in a sealable NMR tube, the alkylidene
complex W(NPh)(CHCMe3)(PEt3)[(Me 3 SiN)2C6H4], 37, was observed. However,
when trying to isolate 37 on a preparatory scale, a mixture of the alkylidene and the
metallacyclobutane complex was isolated. The lack of phosphorous coupling to the
alkylidene proton in the l H NMR of 37, which was observed as a broad singlet at 9.82
ppm, was evidence of the weak coordination of the PEt3 ligand. Weak coordination was
also evident from the 31 P NMR spectrum. The PEt3 was observed as a broad singlet at
-1 1.42 ppm; no 183 W satellites were observed as was the case with the PMe3 adduct of the
alkylidene. As expected, when PMe3 was added to a C^ solution of 37, immediate
formation of the PMe3 adduct, 36, was observed by ! H NMR. Using other phosphines
46
did not lead to the isolation of new alkylidenes, only decomposition or formation of the
metallacyclobutane complex was observed by *H NMR. These reactions were attempted
using PMePh2, PCy3, and PPh3. When quinuclidine, N(CH2CH2)3CH, was heated in a
C6E>6 solution of the bis-neopentyl product, the metallacycle was the only product
observed. This was curious since quinuclidine serves as a a-donor for other electron
deficient organometallic compounds, including a number of alkylidenes. 52 Only
decomposition was observed when THF or DME were utilized as the a-donor ligands.
One property of the new alkylidene which was promising was the thermal stability
of the molecule. A NMR tube containing a C7D8 solution of the PMe3 adduct, 36, can be
heated to 90 °C over days with no observed decomposition in the l H NMR spectrum.
Even though more alkylidenes could not be prepared, the isolation of this new alkylidene
offers a starting point for a study into the metathesis activity of this chelated alkylidene.
Although it would have been desirable to be able to prepare more derivatives of alkylidenes
using this new o-phenylenediamine ligand system it is not unusual to see this type of
reactivity. The formation of alkylidenes by means of a-abstraction of an alkyl proton is a
delicate reaction. There are many factors which influence the reaction products. The
sterics of the ancillary ligands and bis alkyl groups play important roles, as well as the
electronics of the ancillary ligands. These factors play important roles not only in the a-
abstraction reaction, but also in the stability of the alkylidene itself. There are many
decomposition pathways available for alkylidenes, and the balance of steric and electronic
factors of all the substituents must be carefully controlled for isolation of a stable
alkylidene. 54
3.4. Metathesis activity of WfNPh^CHCMe^HPMe^rfMe^SiNbC^ H^l. 36.
Before examining the metathesis reactivity of the alkylidene, the mechanism of this
reaction should be considered as well as how it applies to the known structure of 36.
47
Schrock has done extensive studies 8 which have concluded that in olefin metathesis
reactions the olefin prefers to attack the C-N-0 face in the alkoxide alkylidenes. This
would translate to the C-Ni m ido-N a mido face in the chelated alkylidene. The open
coordination site in 36 is trans to the alkylidene carbon, where, if the olefin coordinated,
rearrangement of a six-coordinate complex would be necessary. The most likely
mechanism for olefin metathesis with this new alkylidene involves prior dissociation of the
PMe3 ligand, followed by attack of the olefin on the vacant coordination site at the C-
Nimido-Namido face of the molecule. Support for this mechanism will be offered
throughout the discussion.
When a pentane solution of W(NPh)(CHCMe3)(PMe3)[(Me3SiN)2C6H4], 36, was
refluxed with one equivalent of diphenylacetylene, a metallacyclobutene complex,
W(NPh)[C(H)(r-Bu)C(Ph)C(Ph)][(Me 3 SiN)2C6H4], 38, was isolated as a red oil eq 3.8.
In the ! H NMR spectrum a singlet was observed at 2.82 ppm (J 2 w-H = 8 Hz)
Me 3 S
i K X
> X R .A 1
N PMe 3 ph
Me 3 Si 36
Ph eq3.8
corresponding to the oc-proton of the metallacyclobutene complex. Metallacyclobutene
complexes of tungsten are quite common, arising from the metathesis of alkylidenes with
diphenylacetylene. 55 Although the reaction took place under relatively mild conditions by
heating to 35 °C, it is important to note that the reaction must be carried out in an open
system. A different result is observed if the phosphine is not liberated from the reaction
mixture. In a sealable NMR tube, a C6D6 solution of 36 and diphenylacetylene was
warmed to 50 °C for 3 days. The l U NMR reveals the formation of 38 within 10 hours,
however, after 3 days, a singlet was apparent at 5.50 ppm, as well as a much smaller
48
singlet at 5.45 ppm. A broad singlet was observed at 0.90 ppm, presumably a new PMe3
resonance. The new product was apparently a vinyl alkylidene, arising from the PMe3
induced ring opening of the metallacycle, eq 3.9.
Me 3 Si Yh L^ Me 3 Si Y
?X~ x N PMe 3
PMe 3 ff'V *"'4K P1 \ eq3.9
W
H
50 °C V^v /
N
/ Ph
Me 3 Si
The observation of two new olefinic resonances was most likely due to formation of both
cis and trans isomers of the vinyl alkylidene. This reaction has been observed for other
metallacyclobutene complexes when a-donor ligands are added. 55
The ring opening metathesis polymerization (ROMP) of norbornene, NBE, was
chosen in order to investigate the olefin metathesis activity of 36. The alkylidene, 36,
polymerized 25 equivalents of NBE in 10 minutes. Analysis of the polymer using GPC
techniques reveals a very high molecular weight for the polynorbornene. The molecular
weight was determined to be 61,000 g/mol versus a polystyrene standard. However,
Schrock and Grubbs have determined that a conversion factor of 2.2 is appropriate for
polynorbornene versus polystyrene. 17 This would make the corrected M n = 27,000 g/mol.
This was still enormous compared to the molecular weight which would be expected if all
the catalyst was active. If 100% of the catalyst was initiated and propagating, the molecular
weight should be near 2500 g/mol. This result showed that less than 10% of the catalyst
was active. This result was consistent with the prediction that phosphine must be lost in
order for the olefin to coordinate to the metal center. Also, in order to observe such a high
molecular weight, the rate of the propagation step must be much faster than the rate of the
initiation step. Figure 3.8 demonstrates this as well as the dependence the reaction would
have on the presence of PMe3 in the reaction mixture.
49
Grubbs studied the effect PMe3 had on the ROMP of cyclobutene 56 by Schrock's
catalyst, W(NAr)(CH-t-Bu)(0-t-Bu)2, Ar = 2,6-diisopropylphenyl. The observations
made by Grabbs were consistent with the ROMP of NBE by the catalyst, 36. In order to
observe the effect of added PMe3, 36 was dissolved in toluene in the presence of ten
equivalents of PMe3. A toluene solution of 150 equivalents of NBE was then added and
the mixture was stirred for one hour. Precipitation with methanol gave a 80% yield of
polynorbornene. The lack of consumption of the monomer, even over the longer reaction
time, demonstrates the effect of PMe3 on the rate of the reaction. Analysis of the polymer
using GPC techniques versus a polystyrene standard gave a corrected M n = 35,000 g/mol.
The theoretical M n , 14,124 g/mol, was roughly 50% of the observed M n , compared to less
WF^ ^=f W=^ +™e3 (1)
PMe 3 A B
X + JK _^ [Wr =-O^Y
B C
[W^O^ + PM03 ^ ^V^O^
k-3 I
C PMe 3 D
(3)
Figure 3.8. Kinetic scheme for the polymerization of norbornene by 36.
than 10% for the uninhibited polymerization reactions. All of the GPC data for the NBE
polymerization reactions can be found in Table 3.2. The percentage of active catalyst has
been increased dramatically by the addition of PMe3. It is important to note how the
phosphine is affecting the polymerization. The added PMe3 must be hindering propagation
to a much greater extent than it is hindering initiation. Grubbs measured the Keq of PMe3
50
binding to both the uninitiated catalyst, A, and the propagating alkylidene, D. 56 It was
observed that the PMe3 binds much more strongly to the propagating alkylidene than the
uninitiated catalyst. This large difference in binding energy virtually stalls the propagation
of the polynorbornene, allowing much more alkylidene to initiate. For the polymerization
of NBE using 36 as the catalyst in the presence of PMe3, the reaction was slowed to such
an extent that after an hour, the reaction only reached 80% completion. But, judging from
the M n of the polynorbene polymers formed, the percentage of active catalyst was still well
below 100%.
The percentage of active catalyst was normally observed to be between 40% and
60% when ten equivalents of PMe3 were used. So, in the inhibited polymerization of NBE
using 36, although the added phosphine makes k? » k_i, k-i was still much larger than
ki. If k_i > ki, then the observed percentage of active catalyst was understandable. At
room temperature, an equilibrium was observed between A and B for Grubbs' system,
with the equihbrium favoring B. 56 At room temperature, no equilibrium was observed for
36, the PMe3 was tightly bound with distinctive 183 W satellites (^w-P = 128 Hz).
The nature of the propagating alkylidene was also observed in an NMR tube
reaction. Five equivalents of PMe3 and five equivalents of NBE were allowed to react with
36 in C6D6. After one hour the l B. NMR spectrum of the reaction revealed that only 80%
of the NBE was consumed. Also, ca. 40% of 36 was converted into propagating
alkylidene. Two broad resonances were observed at 9.09 and 9.31 ppm. These peaks
correspond to the syn and anti isomers of the propagating alkylidene species. 17 ' 56
One property that was not mentioned about the poly(norbomene) polymers
catalyzed by 36 was the molecular weight distribution. The polydispersity index, PDI, is a
measure of distribution of the molecular weight of the polymer chains and is calculated by
M w /M n where M w is the weight-averaged molecular weight and M n is the number-average
molecular weight. All of the polymers which were prepared displayed very narrow
polydispersities, regardless of whether or not the polymerizations were inhibited by PMe3.
51
A comprehensive theoretical study was done by Gold 57 in order to understand the
relationship between the observed PDI values and the relative rates of propagation and
initiation, kp/ki. This study, simplified by others, 58 allows a determination of the
theoretical M w /M n based on kp/ki. The formula takes into account the initial concentrations
of catalyst and monomer, and the concentrations of catalyst and monomer at any given
time.
From NMR experiments, after 30 minutes the uninhibited NBE polymerization has
10% active catalyst with 40% of the monomer consumed. This gives a relative kp/ki of
115. This was extremely fast although the high molecular weights observed agree with this
calculation. In a similar experiment inhibited by 5 equivalents of PMe3, the relative kp/ki
was observed to be 30. The effect of the PMe3 can be seen on the relative rate, however, a
kp/ki of less than 1 would serve to initiate all the catalyst and give better control of the
molecular weight of the polymerization. From Gold's calculations, 57 relative kp/ki's of
this magnitude should give PDI values between 1.005 and 1.12.
Table 3.2. Polymerization of NBE using 36, inhibited vs. uninhibited.
Inhibited with 10 equivalents of PMe3
eq's of NBE
time
150
lhr
1000
lhr
163
3 hrs
70
4hrs
25
5 min
100 b
5 min
342
10 min
52
lhr
Mn/ corrected 3
PDI
Mn/ theoretical
% vield
35,000 g/mol
1.01
14,124 g/mol
80
104,000 g/mol
1.00
94,217 g/mol
65
94,000 g/mol
1.07
15,357 g/mol
85
126,000 g/mol
1.07
6,592 g/mol
88
Uninhibited
28,000 g/mol
1.12
2,354 g/mol
90
37,000 g/mol
1.07
9,517 g/mol
90
120,000 g/mol
1.03
32,202 g/mol
90
115,000 g/mol
1.04
4,888 g/mol
95
a. A correction factor of 2.2 was applied for polynorbornene vs. polystyrene.
b. The polymer was end-capped with benzaldehyde after 5 minutes.
52
The catalytic reactivity of 36 has been examined for other systems as well. The
alkylidene, 36, catalyzes the polymerization of cyclooctene, however, only at elevated
temperatures. This supports the mechanism of dissociation of PMe3 before the olefin can
attack. The ROMP of cyclooctene has a higher activation barrier than NBE since there was
much less ring strain to be relieved and the NBE is much smaller, allowing NBE monomer
to coordinate more readily to an open coordination site of the catalyst. The ADMET
polymerization of 1,9 decadiene has also been investigated. It was already discussed that
36 is stable to thermal decomposition in refluxing toluene, therefore, it should be a
candidate for a thermally stable ADMET catalyst. Observations did not agree with this
assertion. The alkylidene does catalyze the ADMET oligomerization of 1,9-decadiene,
however, the reaction never proceeded past dimers and trimers. It has been suggested that
36 has a preference for internal olefins, causing unproductive metathesis, however this or
any other explanation has not been substantiated.
One aspect of the ADMET reaction which was observed was the poisoning of the
catalyst by the ethylene produced in the reaction. When ethylene was bubbled into a CyD6
solution of 36, the J H NMR initially reveals what appears to be a metallacyclobutane
complex with an cc-t-butyl group. There were multiplets at 2.40 ppm, 2.62 ppm, and 3.76
ppm in a 1:1:1 ratio. A new singlet at 1.20 was also observed in a 9:1 ratio with the
singlets. Over time these resonances diminished as resonances grew in which correspond
to a unsubstituted metallacyclobutane complex. The l H NMR reveals multiplets at 1.80
ppm, 1.91 ppm, 2.20 ppm, 2.58 ppm and 2.75 ppm in a 1:1:1:2:1 ratio. Figure 3.9
shows the scheme by which the a-t-butyl metallacyclobutane is formed and then further
reacts to give the unsubstituted metallacyclobutane complex. Although there was no other
spectral data to support this mechanism, this appears analogous to the behavior displayed
by Schrock's catalyst. 48 ' 59 The peak positions of both metallacycles correspond to
observations made for the alkylidene, W(NAr)(CH-t-Bu)(OR)2 and ethylene. 59
Examination of the room temperature l H NMR over the course of the reaction did not
53
reveal the intermediate methylidene complex, which must be formed before the
unsubstituted metallacycle can be formed.
[W]
t
PMe 3
[W]
X
>!
[W]
t
-CMe 4
+ PMe 3
H
- PMe 3 j ^H
PMe 3
Figure 3.9. Proposed mechanism for formation of an unsubstituted
metallacycle from the reaction of 36 and excess ethylene.
Recently, the applications of ADMET have been expanded to the depolymerization
of unsaturated polymers. Wagener has utilized Schrock's catalyst in order to depolymerize
1,4-polybutadiene, end-capped with a silylene. 60 Although 36 proved unsuccessful for
the polymerization of 1,9-decadiene, possibly because of a preference for internal olefins,
its activity as a depolymerization catalyst was investigated. 500 equivalents of 1,4-
polybutadiene was dissolved in minimal toluene in the presence of 36. After 24 hours,
500 equivalents of the end-capping group were added. GPC analysis revealed that the
depolymerization was successful. Only monomer and dimer were present. Currently,
further work is being done on this reaction.
In this chapter, the substitution of the chlorides in 14 led to the isolation of
numerous new alkyl complexes. The chemistry of the bis-neopentyl derivative, 25, led to
the isolation of a new metallacycle and new alkylidene complex. The metathesis reactivity
of the alkylidene, 36, was investigated and shown to be inhibited by the addition of PMe3.
54
The reactivity of the bis-neopentyl derivative, 25, involving molecular hydrogen will be the
focus of Chapter 4, and will draw on many of the same principles discussed in this chapter.
CHAPTER 4
FORMATION OF W(VI) HYDRIDES FROM THE BIS-ALKYL COMPLEXES
4.1. High Oxidation State Transition Metal Hydride Complexes
The synthesis of high oxidation state transition metal hydride and polyhydride
complexes is a highly active area of chemical research. 61 - 62 Complexes containing M-H
bonds have long been known to be important intermediates in a plethora of catalytic
processes. 62 ' 63 The hydrogenation of olefins, both catalytic and stoichiometric, is one of
the most important functions of transition metal hydride complexes. 61 ' 64 Recently,
Rothwell even demonstrated the catalytic hydrogenation of benzene using a tantalum(V)
hydride complex. There are a number of methods that have been utilized in the preparation
of these hydride complexes. One common preparative method is the high pressure
hydrogenation of metal-alkyl bonds. 61 ' 62 Another means of preparing hydride complexes
is the oxidative addition of hydrogen to lower oxidation state compounds such as W(rV)
and Ta(ni). 61 ' 62 ' 66 Transition metal hydride complexes have also been prepared by
utilizing hydride reagents such as n-Bu3SnH or LiBEt3H 67 Because of its small size,
many hydrides have coordination numbers greater than six. Also, most monomelic
hydrides are stabilized by strong o-donors ligands, such as phosphines.
4.2. Preparation of W(VD Hydride Complexes.
There have been many reports of the hydrogenation of high oxidation state alkyl
complexes to give hydrides, however, frequently these reactions are performed under
forcing conditions (extremely high pressures of hydrogen in the presence of phosphine
ligands at elevated temperatures). 61 - 62 Rothwell observed the reaction of hydrogen and
55
56
Ta(R)2(OAr)3 to give Ta(H)2(OAr)3(PR.3) in the presence of phosphine. 68 This reaction
was carried out at 90 °C under 8300 kPa of hydrogen for 24 hours eq 4.1. These
OAr OAr
-OAr + PMe 2 Ph ^ H 2 (1200 psi) , p^p^Ta _ Ar eq4.1
90°C,24hrs -jT \
R
R-..
OAr
R = CH 2 C6H4-p-Me;
OAr - OC 6 H3-2,6-Pi i 2
OAr
conditions are typical for the hydrogenation of alkyl compounds and are quite harsh.
Similar conditions were not necessary for the hydrogenation of some of the bis-alkyl
complexes discussed in Chapter 3. When W(NPh)(CH2CMe3)2[(Me3SiN)2C6H4], 25,
was placed under two atmospheres of hydrogen in the presence of two equivalents of PMe3
at room temperature, the conversion of the bis-neopentyl to a new dihydride complex was
complete in less than two hours. The dark brown solution turned magenta, and small red
crystals precipitated from solution eq 4.2. The new complex was the seven coordinate
dihydride, W(NPh)(H)2(PMe3)2[(Me3SiN) 2 C6H4], 39.
Me 3 Si //}
\ Me 3 P 1=/
+ 2 PMe3
H 2
hexanes
room temp
/>
N
W-
'/
AX
Me3P
H eq4.2
Me 3 Si
39
Compound 39 was characterized by multinuclear NMR and X-Ray
crystallography. At room temperature, the *H NMR spectrum reveals the hydride
resonances as a broad triplet at 9.28 ppm with a peak separation of 38 Hz. The two PMe3
groups appeared as a singlet at 1.04 ppm, while the silyl methyls were inequivalent singlets
at 0.79 and 0.81 ppm, respectively. The two phosphines were observed as a singlet at
57
-24.46 ppm ( ! Jw-H = 188 Hz) in the 31 P NMR spectrum. When the *H NMR spectrum
was taken at -50 °C, numerous changes were observed. First of all, the PMe3 resonance
resolved into a triplet with a peak separation of 3 Hz at 0.84 ppm. Secondly, the silyl
methyls separated further, resonating at 0.69 and 0.75 ppm. The hydrides appeared as a
doublet of doublets at 8.92 ppm and 9.06 ppm respectively. The apparent coupling was 37
Hz.
Unfortunately, high quality single crystals of 39 have not yet been obtained.
Numerous attempts were made to acquire crystallographic data on 39. Some data was
collected although an accurate structure could not be determined. The data suggest the
presence of frarcs-phosphines with the amido and imido nitrogens in the equatorial plane.
In order to have equivalent phosphines and inequivalent hydrides, the hydrides probably lie
cis to each other, in the plane of the imido and amido nitrogens. This geometry, shown in
eq 4.2, should give an ABX2 resonance for the hydrides, which would be a doublet of
triplets. The doublet of doublets observed at low temperature are very broad and may be
due to a second order effect. A concerted effort is currently underway to obtain an X-ray
structure of 39. The PMe2Ph derivative, W(NPh)(H)2(PMe2Ph) 2 [(Me 3 SiN) 2 C6H4], 40,
was prepared in an analogous reaction. The hydride ligands were observed as a broad
singlet at 9.80 ppm in the l H NMR spectrum at room temperature. At -50 °C, a triplet at
9.56 ppm was observed with 39 Hz coupling, analogous to 39. The 31 P NMR spectrum
revealed a singlet at -22.48 ppm with 183 Hz 183 W satellites. The PMe2Ph derivative was
prepared in the hopes growing better crystals, since most of the structurally characterized
hydrides are the PMe2Ph derivative. 61 - 62 ' 67
The seven-coordinate dihydride, 39, should serve as an excellent model to study
the reactivity of dihydride complexes. Therefore, a more convenient route to the synthesis
of this compound would be useful. Avoiding the alkylation step and adding hydride to the
dichloride, 14 would be a viable route. Two equivalents of superhydride, LiBEt3H, were
allowed to react with 14 in cold Et20. Work-up afforded 39 as a brown-red powder.
58
There was residual BEt3 which could not be removed from the compound. Although this
reaction was important in showing the ability of 14 to add hydride, it was not employed to
make the hydrides for the reactivity studies.
When two equivalents of PCy3 were utilized as the phosphine ligands, the steric
bulk of the ligand prevented isolation of the analogous bis-phosphine complex. Although
combustion analysis has not been performed because of the excess phosphine present, the
spectral data are consistent with the isolation of the monophosphine complex
W(NPh)(H)2(PCy3)[(Me 3 SiN)2C6H 4 ], 41, eq 4.3. The X H NMR spectrum of 41
reveals a doublet at 1 1.35 ppm ( 2 Jp-H = 83 Hz).
Me3Si
Me 3 Si T \
Vt N /
W + pCy 3
xK^ f "N . / hexanes
N \ room temp
Me 3 Si 25
Me 3 Si
Satellites due to the !83\y lj w . H coupling were observed at 64 Hz. The silyl methyl
groups were observed as a singlet at 0.83 ppm. The 31 P NMR spectrum of 41 reveals a
singlet at 66.53 ppm (^p-H = 83 Hz).
The chelating nature of the bis-amide ligand again dictates the geometry of the
molecule. Rothwell prepared Ta(OAr)2Cl(H)2(L)2 derivatives using PMe3, PMe2Ph,
PMePh2. 68 The structures of these compounds reveal that the phosphines are always trans
to one another. In these compounds, the aryloxides are always trans to one another as
well. This differed from 39 and 40 in which the amide nitrogens must be cis to one
another because of the chelating nature of the ligand. In order to investigate the role of the
trans phosphines, and to fine out whether or not cis phosphine complexes were stable, a
chelating phosphine was selected. Diphenylphosphinoethane, DPPE, was utilized in a
59
reaction similar to eq 4.2. The new hydride was found to be
W(NPh)(H)2(DPPE)[(Me3SiN)2C 6 H 4 ], 42, eq 4.4.
The *H NMR spectrum of 42 reveals a very symmetrical molecule. The silyl
methyls were observed as a singlet at 0.49 ppm. The methylene protons of the DPPE
ligand were observed as multiplets at 2.23 and 2.42 ppm. The hydrides were equivalent at
all temperatures observed. At room temperature the hydrides appeared as a complex
multiplet which can be viewed as the X part of an ABX2 spin system where the phosphines
are A and B. Satellites due to 183\y coupling were observed at 58 Hz for each of the peaks
in the spectrum. The *H NMR spectrum of the hydride region can be seen in Figure 4.1 .
Me 3 Si
v N vii/~^ „ 2 rrvM^ *
W +DPPE «- i W- P eq4.4
Ay \-f ***** [ IA / 1 V Ph
N \ room temp \^ x j/ ?—-/
Me 3 Si 25 / Ph Ph
Me3Si
42
The phosphines were inequivalent in the 31 P NMR spectrum, and appear as doublets, at
-12.70 and 30.43 ppm, respectively ( 2 Jp.p = 83 Hz). The geometry of this seven-
coordinate dihydride can be inferred from the NMR data. Having one leg of the DPPE
bisect the two hydrides is the only possible geometry giving both equivalent silyl methyls
and hydrides as well as inequivalent phosphines.
There are few examples of high oxidation state hydride complexes where strong o~-
donor ligands are not coordinated to the metal center. Coincident with this is that there are
few coordinatively unsaturated high oxidation state hydride complexes. One of the few
examples resulted when Rothwell hydrogenated Ta(OAr)3(CH2C6H4-4-Me)2 under 1200
psi of hydrogen at 90 °C for 24 hrs to give Ta(H)(OAr)4 in low yield. 68 The monohydride
60
R "*
U
'* g
CO
o
W
CM
'. §
O
rt
o
"Eb
S
o
O
•s
O
a
o
P«
P4
as
u
61
is presumably formed in a ligand exchange reaction. There are also metallocene derivatives
of the type CP2MH2, but these will not prove insightful to this discussion. 69
When phosphine was present upon hydrogenating the bis-neopentyl complex, 25,
the reaction was complete in a matter of hours. When no phosphine was added to the
reaction, the hydrogenation proceded much more slowly, and allows an examination of the
mechanism of the reaction. When H2 gas was sealed in an NMR tube containing a C^Ds
solution of 25, hydrogenation of the metal carbon bonds took place in a matter of days.
The rate was dependent on the pressure of H2 gas. When a very low pressure of gas, < 20
psi was sealed in the tube, the reaction took nearly a week to reach completion. However,
when 30 psi of H2 was used, the reaction was complete in about 36 hours. The product is
only observable under an atmosphere of H2 gas. The product of the hydrogenation was
presumably a dimer due to interpretation of the NMR data. The silyl methyl groups were
observed as a singlet at 0.33 ppm in the *H NMR spectrum. Two equivalents of
neopentane were observed at 0.93 ppm. The spectrum also reveals a singlet at 15.68 ppm
with 168 Hz 183 W satellites corresponding to the two hydrides. The tungsten satellites
were actually observed as doublets, J = 4 Hz. The observation of the tungsten satellites as
doublets was the key evidence in proposing a dimeric structure. Cotton observed a similar
coupling effect in the W2Cl4(NHCMe3)(PR3)2 system. 69 The only observable satellites
will be from a dimer with only one 183 W, due to only 14% abundance. This would
constitute an ABX spin system, resulting in a doublet of doublets. The hydride resonance
is shown in Figure 4.2. The shift of the hydrides was in the normal range for high
oxidation state group 5 and 6 complexes in the literature. 61 " 68 Evidence for proposing
bridging imido groups will be given later in the chapter. The reaction is shown in eq 4.5.
When the sample was evaporated to dryness, the dihydride isomerized or rearranged,
forming what appeared to be a bridging hydride. When the sample was redissolved in
C6D6, the *H NMR spectrum changed dramatically. At room temperature, the hydrides did
not appear in the spectrum, although a broad increase in the integral was observed between
Me 3 Si x
N ^ N
1 25
Me 3 Si 25
■f
H 2 , 20 psi
»
hexanes
room temp
36 hours
62
Me 3 Si
SiMe 3
\ /
N* H N H ,N
Me 3 Si [l] SiMe 3
43
11 and 13 ppm. When the sample was cooled to -25 °C, a sharp singlet at 12.58 ppm and a
broad singlet at 15.80 ppm were observed in a 1:1 ratio. When the sample was cooled
further, to -50 °C, the sharp singlet remained unchanged while the broad singlet split into
two broad singlets at 15.28 ppm and 1 5.98 ppm respectively. The ratio of the three peaks
was observed to be 2:1:1. The broad singlets are consistent with being bridging hydrides,
while the sharp singlet appears to be the terminal hydrides. The sharp singlet actually had
satellites at 53 Hz and 100 Hz. Although the true identity of the molecule cannot be
confirmed, it is assuredly still a dihydride complex of sorts. When two equivalents of
PMe3 were added to the sample, the bis-phosphine dihydride, 39, was formed by
observation of the l H NMR. There is not enough known at this time to make more
substantial conclusions, but work is continuing in this area.
As was mentioned earlier, since the hydrogenation, at very low pressures of H2,
takes a number of days, an opportunity to observe intermediates and deduce a mechanism
was presented. In an NMR tube reaction, 25 was dissolved in C6D6 and sealed under an
atmosphere of less than 20 psi H2. After twelve hours, the l U NMR revealed four
compounds in the reaction mixture. There was 25% starting material, neopentane, and two
new compounds, the metallacyclobutane, 35, and a monohydride complex, 44 eq 4.6.
The spectrum reveals the two doublets, at -1.7 and 2.1 ppm, which correspond to the
metallacyclobutane complex discussed in Chapter Three.
63
64
Me 3 Si
a:
vll
w
Me 3 Si
./
25
■f
H 2 , <20psi
room temp
1 2 hours
Me,Si
"^Y
Nfc
N
<6*
Me,Si
vll.
w
44
•c6 J
Me 3 Si 35
eq4.6
The monohydride, W(NPh)(CH2CMe3)(H)[(Me3SiN)2C6H4], 44, was characterized by a
singlet at 18.43 ppm (^w-H =151 Hz). The methylene protons of the monohydride-
neopentyl complex appeared diastereotopic with a doublet at 2.60 ppm and a broad singlet
at 3.28 ppm. As the reaction was observed over the course of the following 3 days, the
bis-neopentyl complex, 25, disappeared completely and the dihydride complex, 43, grew
in. Over the course of a number of trials of this NMR tube reaction, it was observed that
the bis-neopentyl reached at least 90% completion before dihydride formation initiated.
The metallacyclobutane complex was thought to be in an equilibrium with the
monohydride complex under an H2 atmosphere. The metallacycle was formed when H2
was lost from the monohydride by a net y-hydrogen elimination mechanism. The reverse
reaction takes place when H2 was added across one of the W-C bonds of the metallacycle
eq 4.7. This equilibrium was
-H 2
+H 2
eq4.7
Me 3 Si 35
demonstrated by adding H2 to an NMR tube containing a CgDg solution of 25, then
degassing the reaction after eight hours. The l H NMR spectrum, which was taken
immediately after degassing, revealed the three compounds expected, 25, 35, and 44 in
roughly a 1:1:3 ratio. Over the course of two weeks, the reaction was degassed
65
periodically. During this time, the bis-neopentyl complex was completely consumed.
Also, as the reaction proceeded, the monohydride decreased and was only observable in
trace amounts. Figure 4.3 demonstrates how only a catalytic amount of hydrogen was
necessary for complete conversion of the bis-neopentyl complex to the metallacycle.
Figure 4.3. Formation of the metallacycle, 35, by the addition of a
catalytic amount of H2 to the bis-neopentyl complex, 25.
All of the observations which have been made pertaining to the hydrogenation of
25 in the absence of PMe3 were from NMR tube experiments. When complete
hydrogenation of 25 was carried out on a preparatory scale only the bridging hydride was
isolated. It appears to be the same bridging hydride which was observed when 43 was
evaporated to dryness and redissolved in C6D6. When a pentane solution of 25 was stirred
under two atmospheres of H2 for 36 hours and cooled to -10 °C, dark crystals were formed
which were suitable for X-ray diffraction.
The X-ray structure revealed a unique dimeric structure. The thermal ellipsiod plot
of 45 is shown in Figure 4.4. The structure was interesting since there is a neopentyl
66
<-l-c
o
o
-a
-t-H
o
CO
.&
»-— t
W
13
3
67
group on one of the tungsten atoms and not on the other. Both of the imido groups were
bridging and both the nitrogen's lie slightly closer to the tungsten without the neopentyl
group, probably in order to relieve steric congestion. The bridging hydride was located
and refined. It was found to be 2.07(10)A from Wl and 1.87(1 1)A from W2. Although
the terminal hydrides were not found in the difference Fourier map, there appears to be
open coordination sites which could accommodate the terminal hydrides, both on the
unsubstituted tungsten. The open coordination sites are in the axial positions. The fold
angle of the bis-amide ligand on the neopentyl substituted tungsten was 54 °. The fold
angle of the bis-amide ligand on the unsubstituted tungsten was °. The planarity of the
bis-amide ligand would be due to the seven-coordinate nature of the tungsten atom. The
l B. NMR of 45 reveals that the molecule is quite fluxional, with all of the hydrides
appearing as a very broad singlet at 12.9 ppm.
Hydrogenation of the bis-neophyl complex, 26, gave results similar to 25.
However, the metallacycle was always observed in a much lower ratio than in the bis-
neopentyl hydrogenation. This was probably because the p-methyl, {3'-phenyl-
metallacyclobutane complex was much less stable than the p,pY-dimethyl-
metallacyclobutane complex. Therefore, it loses H2 and reverts to the monohydride much
more readily.
Another means of investigating this equilibrium was to examine the effect of added
phosphine to the reaction mixture. Once the equilibrium was established and the reaction
degassed, one equivalent of PMe3 was added to the reaction mixture. Surprisingly, the
alkylidene, 36, was formed almost immediately. This reaction proceeds by an cc-hydrogen
abstraction from the monohydride complex, eliminating H2, or possibly rearrangement of
the metallacycle. The H2 released then adds to the metallacyclobutane, forming more
monohydride to react with the phosphine. The mechanism for this reaction can be seen in
Figure 4.5. This would be the first example of an a-abstraction involving the loss of
hydrogen to form an alkylidene. Undoubtedly, reductive elimination of neopentane would
68
be a more expected than a-abstraction. The implications of such a mechanism contradict
many of the criterion which dictate a-abstraction reactions in high-oxidation state transition
Me 3 Si' 36
Figure 4.5. Mechanism for the formation of the alkylidene by
a-abstraction from the equilibrium mixture of 35 and 44.
metals. Certainly no steric relief was gained by the elimination of H2. The W-C a -Cp angle
decreases from an alkyl to an alkylidene but that is overshadowed by the addition of PMe3
to the metal center.
This brings up the question of the hydrogenation of the alkylidene. When a C&D6
sample of 36 and one equivalent of PMe3 was placed under two atmospheres of H2, the
dihydride, bis-phosphine complex, 39, was formed in a matter of hours eq 4.8. A
different observation was made when the alkylidene was hydrogenated under an extremely
low pressure of H2 in the absence of 'added' phosphine. Over the course of ten days, the
alkylidene was completely consumed to give a one to one mixture of two products and one
equivalent of neopentane. The two products were the dihydride, bis-phosphine complex,
39, and the metallacyclobutane complex, 35. The two products were most likely formed
69
by the disproportionation of the intermediates since there were less than two equivalents of
H2 added.
,\^r) u "\^P
Me 3 Si tik
Vt It
- N vll.
^
N
A /\ + pmc 3 H? ' 2atm > I /T>T H eq4 " 8
N PMe 3
Me 3 Si / 36 I Me 3 P
Me 3 Si 39
N
It cannot be denied that there appears to be a number of loose ends in the chemistry
of these new hydride complexes, especially in the absence of phosphines. However, it is
also undeniable that there was a wealth of information that lead to the conclusions which
were made. Although isolation of a number of these compounds is unlikely due to their
instability, crystallographic data on one or more of these compounds would be quite
insightful. The discovery of an example a-hydrogen abstraction involving the
monohydride-neopentyl has enormous implications and will be investigated further.
4.3. Reactivity of the Dihydrides.
High oxidation state transition metal hydrides complexes are known to hydrogenate
olefins both stoichiometrically and catalytically. 62 - 63 Rothwell even demonstrated the
hydrogenation of arenes using Ta(V) dihydrides.65 Coordination of the olefin was an
essential step in the reaction. Olefins are ^-acceptor ligands and require filled metal d-
orbitals to facilitate back-bonding. Therefore cP olefin complexes are unlikely.
Nonetheless dS and <fi complexes should have sufficient orbitals to overlap with an olefin
acceptor orbital, stabilizing a 7t-olefin complex. Ligands with a strong electronic donation
to the metal center should aid in the isolation of coordinated 7t-olefin complexes. Imido
ligands (=NR) 2_ are strong 7t-donors because of the lone electron pair and should aid in the
70
isolation of 7t-olefin complexes. Strong a-donors, such as phosphines should also aid in
creating a suitable electronic environment for 7t-olefin complexes. Currently, there are very
few examples of d 1 or d 2 Tt-olefin complexes which have been thoroughly characterized. 71
Therefore, the isolation of jt-olefin complexes is essential to the advancement of this
chemistry.
Initial investigation into the reactivity of some of the phosphine stabilized hydride
complexes, 39 and 42, has begun. When a C6D6 sample of
W(NPh)(H)2(PMe3)2[(Me3SiN)2C6H4], 39, in a sealable NMR tube was placed under an
atmosphere of ethylene, ethane formation was observed by the observation of a singlet at
1.1 ppm in the *H NMR spectrum. A second equivalent of ethylene was bound to the
reduced metal center, forming the W(IV) ethylene complex, W(NPh)(ri 2 -
C2H4)(PMe3)2[(Me3SiN)2C 6 H 4 ], 46, eq 4.9. The *H NMR spectrum of the ethylene
complex reveals that the compound is quite fluxional at room temperature.
Me 3 Si
\ Me 3 P
w;
Me 3 Si PMe 3 {? ]|
N.
2C 2 H 4
Me 3 P
Me 3 Si
/
+ C 2 H 6 eq 4.9
39
N
/ Me 3 P
Me 3 Si 46
The room temperature X H NMR spectrum is shown in Figure 4.6. The ethylene protons
were observed as two multiplets at 1.96 and 2.19 ppm respectively. The coupled 13 C
NMR spectrum revealed a triplet at 36 ppm corresponding to the ethylene carbons. The
iJc-H coupling of the carbons was 156 Hz, typical for an ethylene complex, indicating that
little 'metallacyclopropane' character was evident 71 . The PMe3 ligands were equivalent
and were observed at 1.05 ppm in the ] H NMR spectrum. At room temperature, the 31 P
NMR spectrum revealed a broad singlet at -23.2 ppm while at -25 °C, a sharp singlet at
-21.77 ppm with 238 Hz 183 W satellites was observed. The silyl methyls appeared as a
71
U
o
CO
cN
*->
cd
SO
&
CO
CO
CS
"en
o
.p-
t*-i
o
o
Pi
»— 1
^°
u
3
•Ml
72
broad singlet, nearly 120 Hz wide, at 0.50 ppm in the l H NMR spectrum at room
temperature. When the sample was cooled to -25 °C, two sharp singlets were observed at
0.39 ppm and 0.42 ppm. A tantalum ethylene complex prepared by Schrock 72 and
tungsten olefin complexes prepared by Nielson 73 show that the ethylene prefers to
coordinate cis to the imido. The ethylene also preferred to coordinate cis to phosphine
ligands. In every case, the ethylene coordinated trans to an 'X' ligand. Nielson obtained
crystallographic data on W(NPh)Cl2(Me2C=CH2)(PMe3)2 which clearly demonstrated this
geometry. 73 The spectral data for 46 were consistent with these compounds and support a
trans phosphine structure. Difference nOe experiments on 46 showed that upon irradiation
of the orf/?o-protons of the imido group, a 4.8% enhancement was observed for the
coordinated ethylene. This substantiates the cis orientation of the imido and the ethylene.
A W(IV) olefin complex was also formed when two equivalents of styrene was
allowed to react with the dihydride, 39. In an NMR tube experiment, formation of
ethylbenzene was observed along with formation of the styrene complex, W(NPh)(r| 2 -
CH2CHPh)(PMe3)2[(Me3SiN)2C6H4], 47. The olefinic peaks were observed as sharp
multiplets at 2.62 and 2.80 ppm and a triplet at 3.87 ppm in a 1:1:1 ratio. The orientation
of the coordinated styrene is not known, although it appears by NMR that only one
orientation is adapted.
When the catalytic hydrogenation of ethylene and cyclooctene was attempted using
the dihydride, 39, mixed results were observed. Cyclooctene and H2 were added to an
NMR sample of 39. Over time, even with mild heating, it did not appear as though any
cyclooctene was hydrogenated by observation of the NMR. It was already known that one
equivalent of ethylene is stoichiometrically hydrogenated by 39, so detection of catalysis
by NMR proved difficult. It appeared as though, over days, that the ratio between the
ethylene and the ethane appeared to decrease. Further work will be focused on this
reaction.
73
The reaction of ethylene and the DPPE dihydride, 41, did not yield an ethylene
complex. Instead, no reaction was observed at room temperature over three days.
However, when a purple C^ solution of 41 and ethylene was heated to 90 °C for 12
hours, the color changed to yellow. The ! H NMR revealed that DPPE had been lost from
the metal center. The resonances corresponding to the hydrides and free ethylene were also
no longer present. The product formed appears to be a metallacyclopentane complex
formed by the addition of two equivalents of ethylene to the metal center. 74 The overall
reaction can be seen in eq 4.10. The complex appeared to have
rr^
Me 3 S
xs C 2 H 4
80 °C
42
+ DPPE eq4.10
a plane of symmetry due to the observation of a singlet at 0.31 ppm in the l H NMR
spectrum and two AA'BB' multiplets at 7.1 1 ppm and 7.41 ppm. The metallacyclopentane
protons were observed as three multiplets, at 1.58 ppm, 2.41 ppm, and 2.89 ppm in a
2:2:4 ratio.
A reaction that is important to mention at this point is the reaction of excess ethylene
with the bis-neopentyl complex, 25. When ethylene was allowed to react with a C^
solution of 25, the ! H NMR revealed that 1-butene was released. The formation of 1-
butene was very slow but very clean, a 60:40 mixture of ethylene and 1-butene was
observed after 14 days at room temperature. Throughout the reaction, the concentration of
25 remained virtually unchanged while formation of other organometallic products was not
observed. After 14 days, the sample was heated to 80 °C for 8 hours. The ! H NMR
spectrum revealed that all of the ethylene had been consumed. There was no bis-neopentyl
complex observable in the NMR, although the large amount of 1-butene obscured much of
74
the spectrum. The sample was degassed thoroughly. The *H NMR revealed that the
organometallic product was identical to the proposed metallacyclopentane complex from the
reaction of 42 and ethylene.
The fact that 1-butene formation was observed without observation of a new
organometallic compound suggests that a very small amount of an active catalyst was being
produced at room temperature. At higher temperature, all of the bis-neopentyl must be
converted to the active catalyst. The formation of 1-butene from the metallacyclopentane
complex would go by a simple (3-hydrogen elimination reaction. Therefore, the formation
of the metallacyclopentane is the key step of the reaction. The formation of
metallacyclopentane compounds from addition of two equivalents of ethylene to a low
oxidation state metal center is well known. 2 ' 74 > 75 These metallacyclopentane complexes
are also known to undergo (3-hydrogen elimination reactions, forming 1-butene. The
formation of a reduced metal species, W(IV), in this case, would be formed by the
reductive coupling of the two neopentyl groups. The mechanism for this reaction can be
seen in Figure 4.7.
Most of the work reported in this chapter involves very recent results, and has
brought up many new questions as well as areas for future work. Other members of the
research group will continue this work, and hopefully continue to make great strides in this
area.
Me,Si
a;
N. N
W'
X
xs C->H.
-(M&jCCHjJj
Mc 3 Si
i-hydrogcn dim.
[W]
>
^
Mc,Si
N*. N
' /"--■~.
coo
McjSi
Figure 4.7. The catalytic formation of 1-butene from the addition of
ethylene to the bis-neopentyl complex, 25.
CHAPTER 5
EXPERIMENTAL
Unless otherwise noted, all procedures were performed under dry argon
atmosphere using standard Schlenk techniques or in a nitrogen atmosphere dry box. All
solvents were dried according to established literature procedures.
*H, 13 C and 31p NMR spectra were recorded on a Varian VXR-300 (300 MHz), a
General Electric QE-300 (300 MHz), or a Varian Gemini-300 (300 MHz) spectrometer.
Chemical shifts were referenced to the residual protons of the dueterated solvents and are
reported in ppm downfield of TMS for *H and 13 C NMR spectra. 31 P NMR were
referenced to an external H3PO4 standard. Elemental analysis were performed by Atlantic
Microlabs, Inc., Norcross, GA.
Preparation of N.N'-bis(trimethylsilyl)-o-phenylenediamine. 1:
Trimethylsilylchloride (12.7 mL, 0.10 mol) was added slowly to a solution of o-
phenylenediamine (5.00 g, 0.047 mol) in 50 mL of Et20. A white precipitate formed upon
addition. Triethylamine (13.9 mL, 0.10 mol) was then added slowly, ensuring that stirring
continued throughout the addition. After stirring for 3 hours at room temperature, the
mixture was filtered and the solid was washed twice with 15 mL of Et20. The filtrate was
stripped of solvent under reduced pressure to give 10.2 grams of a yellow solid; yield,
86.8%. M.P.;29.5°C.
75
76
Preparation of Liori^-rNSiMeV bC^FL;!. 2:
A solution of N,N'-bis(trimethylsilyl)-o-phenylenediamine (5.26 g, 20.9 mmol) in
75 mL of pentane was cooled to -78 °C. To this solution, 2 equivalents of n-BuLi (16.8
mL, 41.9 mmol, 2.5 M sol. in hexanes) was added slowly. A white precipitate formed as
gas was evolved. Upon addition, a bubbler was attached and the reaction was stirred at
room temperature for 2 hours under a flow of argon. The mixture was filtered and the
solid dried under reduced pressure. The volume of the filtrate was reduced to 25 mL under
reduced pressure and cooled to -15 °C to give colorless crystals. Yield; 4.93 g (combined),
89.5%.
Preparation of N.N'-bisfdimethylphenylsilylVo-phenylenediamine. 3:
O-phenylenediamine (1.58g, 14.64 mmol) was slurried in 50 mL of hexanes. Two
equivalents of both dimethylphenylsilylchloride (4.90 mL, 29.29 mmol) and triethylamine
(4.08 mL, 29.29 mmol) were added via syringe. The mixture was then refluxed for 12
hours. Upon cooling, a white salt precipitated from solution. The mixture was filtered.
The yellow solution was stripped of solvent under reduced pressure to give 4.86 grams of
a yellow/red solid; yield, 87.0%. Anal. Calc'd for C22H28N2S12: C, 70.15; H, 7.49; N,
7.44. Found: C, 69.89; H, 7.28; N, 7.21.
Preparation of N.N'-bis(methyldiphenylsilyl)-o-phenylenediamine. 4:
O-phenylenediamine (0.64 g, 5.94 mmol), methyldiphenylsilylchloride (2.50 mL,
11.81 mmol) and triethylamine (1.82 mL, 13.00 mmol) were reacted as described above
for 3 to give 2.09 grams of a reddish solid; yield 70.3%. Anal. Calc'd for C32H32N2Si2:
C, 76.75; H, 6.44; N, 5.60. Found: C, 76.39; H, 6.23; N, 5.27.
77
Preparation of N.N'-bis(trimethylsilyl)-4.5-dimethyl- 1 .2-diaminobenzene, 6:
4,5-dimethyl-l,2-diaminobenzene (5.11 g, 37.52 mmol), trimethylsilylchloride
(9.52 g, 75.05 mmol), and triethylamine (10.53 mL, 75.05 mmol) were reacted as
described above for 3 to give 9. 12 grams of a yellow solid; yield, 88.53%. Anal. Calc'd
for Ci 4 H28N 2 Si 2 : C, 59.93; H, 10.06; N, 9.99. Found: C, 60.13; H, 10.29; N, 10.21.
Preparation of N.N'-(trimethylsilyl)-1.8-diaminonapthalene. 7:
1,8-diaminonapthalene (10.61 g, 67.07 mmol), trimethylsilylchloride (17.87 mL,
140.84 mmol), and triethylamine (19.63 mL, 140.84 mmol) were reacted as described for
3 above to give 18.15 grams of a red solid; yield, 89.4%. Anal. Calc'd for C16H26N2S12:
C, 63.49; H, 8.67; N, 9.27. Found: C, 63.17; H, 8.39; N, 9.08.
Preparation of N-phenyl. N'-trimethylsilyl-o-phenylenediamine. 8:
N-phenyl-o-phenylenediamine (1.53 g, 8.28 mmol), trimethylsilylchloride (1.18
mL, 8.50 mmol), and triethylamine (1.08 mL, 8.50 mol) were reacted as described above
for 3 to give 1.64 grams of a reddish solid; yield; 77.2%. Anal. Calc'd for Ci5H2oN2Si:
C, 70.24; H, 7.87; N, 10.93. Found: C, 69.91; H, 7.68; N, 10.73.
Preparation of l^-q PrNHbC^FU 9 and l^NfmCfMebCHoCHfMeWfH^-C^ 10
O-phenylenediamine (2.5 g, 23.12 mmol) and sodium acetate (7.21 g, 87.9 mmol)
were slurried in 15 mL of acetic acid, 20 mL of acetone, and 40 mL of H2O. The mixture
was stirred for 30 minutes in an ice bath. NaBIL; (14.97 g, 277.4 mmol) was added
slowly. Upon addition, the reaction was allowed to warm to room temperature and was
stirred for one hour. NaOH (6 M solution) was added until slightly basic by litmus test.
The mixture was then extracted with Et20 (2 x 20 mL). The Et20 was removed in vacuo to
78
yield a red oil. The oil was separated by flash chromatography on a Silica column using
hexanes. The heterocyclic compound l,2-[N(H)C(Me)2CH 2 CH(Me)N(H)]-C6H 4 10,
was eluted first, solvent was striped in vacuo to give a white powder (1.31 g, 41.1%).
Anal. Calc'd for Ci 2 H 2 oN 2 : C, 75.80; H, 9.47; N, 14.74. Found: C, 75.71; H, 9.64;
N, 14.75. The diamine, l,2-( i PrNH) 2 C6H4 9, was eluted last and was isolated by cooling
the hexanes solution to -78 °C to yield a white powder, which melted to a colorless oil upon
warming (0.87 g, 29.3 %).
Preparation of 1.8-rN(H)C(MebNnHmQ mH4 11
1,8-Diaminonapthalene (2.57 g, 16.25 mmol) and sodium acetate (5.06 g, 61.75
mmol) were slurried in 10 mL of acetic acid, 20 mL of acetone, and 40 mL of H 2 0. After
stirring in an ice bath for 30 minutes, NaBH4 (15.95 g, 285.9 mmol) was added slowly.
Upon addition, the reaction was allowed to warm to room temperature and was stirred for
one hour. NaOH (6 M solution) was added until slightly basic by litmus test The mixture
was then extracted with Et 2 (2 x 20 mL). The Et 2 was removed in vacuo to yield red
powder (2.96 g, 91.9%). Anal. Calc'd for Ci 3 Hi 4 N 2 : C, 78.76; H, 7.12; N, 14.13.
Found: C, 78.22; H, 7.09; N, 14.49.
Preparation of WQCb^NSiMeV bC^FL I. 13:
WOCL4 (1.00 g, 2.93 mmol) and 1.1 equivalents of Li 2 [l,2-(NSiMe3) 2 C6H4] 2
(0.85 g, 3.20 mmol) were combined in a Schlenk tube and cooled to -78 °C. 50 mL of
Et 2 which had been cooled to -78 °C was added. The reaction was warmed to room
temperature and stirred for 8 hours. Solvent was removed under reduced pressure. The
solid was extracted with 50 mL of pentane and filtered through a Celite pad. The dark
solution was cooled to -78 °C to afford a dark red powder (0.39 g, 25.6% yield). Anal.
Calc'd for Ci 2 H 2 2N 2 OCl 2 Si 2 W: C, 27.65; H, 4.26; N, 5.37. Found: C, 27.61; H, 4.29;
N, 5.41.
79
Preparation of WfNP^CbrfNSiMe^ bC^rL I. 14:
N,N'-bis(trimethylsilyl)-o-phenylenediamine 1 (3.83 g, 15.16 mmol) was
dissolved in 30 mL of Et20 and cooled to -78 °C. Two equivalents of n-BuLi (12.13 mL,
30.32 mmol, 2.5 M soln in hexanes) were then added. The reaction was warmed to room
temperature and stirred for one hour. The reaction was recooled and .95 equivalents of
W(NPh)CU(OEt 2 ) (7.10 g, 14.4 mmol) in 20 mL of Et 2 was added. The reaction was
stirred for three hours, then filtered through a celite pad, which, in turn, was rinsed with
more Et20. Solvent was removed under reduced pressure. The dark red solid was washed
with pentane until an orange powder remained. The powder was dried to yield 7.31 g of
14; 85.1%. Anal. Calc'd for Ci 8 H27N 3 Cl2Si2W: C, 36.25; H, 4.56; N, 7.05. Found:
C, 35.91; H, 4.78; N, 6.78.
Preparation of l.S-KoCMe^SiNlC iinm 16 and L8-Li 2 (Me3_SiN)O inH£. 17
1,8-Diaminonapthalene was dissolved in pentane and cooled to °C. Two
equivalents of either KH or n-BuLi were then added. The reactions were allowed to warm
and stirred for one hour. Yellow precipitate formed during the reaction. Cooling the
reaction mixtures to -10 °C afforded nearly quantitative yields of the corresponding salts as
yellow crystals.
Preparation of WfNPh^Cbri^-CNSiMe^ bOinH *!. 18:
l,8-(NHSiMe 3 ) 2 CioH6 7 (1.28 g, 4.23 mmol) was dissolved in 25 mL of Et20
and cooled to 78 °C. Two equivalents n-BuLi (3.38 mL, 8.46 mmol, 2.5 M in Et20) were
added via syringe. The reaction was allowed to warm to room temperature and stirred for
one hour. Over this time the color of the solution changed from red to yellow. The
solution was recooled and .95 equivalents of W(NPh)CU(OEt2) (2.02 g, 4.10 mmol) in a
25 mL Et20 solution were added. The reaction was allowed to warm to room temperature
80
and was stirred for 6 hours. The mixture, which had turned dark red, was filtered through
a celite pad and was washed with Et20 until colorless. The solvent was removed under
reduced pressure and dried for 4 hours. The solid was then washed 3 times with 20 mL of
pentane and dried under reduced pressure overnight. 2.13 grams of a dark red solid were
isolated; yield, 80.4%. Anal. Calc'd for C22H29N3CI2S12W: C, 40.88; H, 4.52; N, 6.50.
Found: C, 40.59; H, 4.21; N, 6.19.
Preparation of WfNPh)Cbr4.5-(CH^ 2 -l-2-(NSiMe2 bC^H 2 1 - 19:
N,N'-bis(trimethylsilyl)-4,5-dimethyl-l,2-diaminobenzene 6 (1.29 g, 4.70 mmol),
W(NPh)C14(OEt2) (2.29 g, 4.65 mmol), and n-BuLi (3.76 mL, 9.40 mmol, 2.5 M in in
Et20)were reacted as described above for 14. 1 .89 g of a red solid were isolated; 64%
yield. Anal. Calc'd for C2oH3iN 3 Cl2Si 2 W: C, 38.47; H, 5.00; N, 6.73. Found: C,
38.29; H, 4.78; N, 6.48.
Preparation g[M^£hiiQ^2^ ) 2UMs^Il^^JS2iE^ 20:
W(NPh)Cl2[(NSiMe3)2C6H4] 14 (0.50 g, 0.84 mmol) and two equivalents of
Ag(OS02CF3)2 (0.43 g, 1.68 mmol) were combined in a Schelnk tube and dissolved in 25
mL of °C Et20. After stirring at room temperature for 8 hours, the Et20 was removed
under reduced pressure. The solid was extracted with Et20 and filtered through Celite until
colorless. The reddish solution was concentrated to 10 mL and cooled to -10 °C to give
0.59 grams of 20 as an orange solid, yield: 85.0%.
Preparation of WCNPrnChCPMe^WNSiMe VbC^Ha l. 21:
W(NPh)Cl2[(NSiMe3)2C<sH 4 ] 14 (0.68 g, 1.14 mmol) was slurried in 30 mL of
pentane. Excess PMe3 (4.55 mL, 2.00 mmol, .44 M in toluene) was added to the reaction.
The reaction immediately turned from redish to deep purple. The reaction was cooled to
-78 °C to give 21 as 0.71 grams of purple crystals, yield; 90.5%.
81
Preparation of WfNPh^CblLWNSiMeV bC^Pkl,
L = THF. 22: 3-Picoline. 23; CPhCN. 2~4:
W(NPh)Cl2[(NSiMe3)2C6H4] 14 was dissolved in a minimum amount of the
solvent, L. The deep purple solution was then added slowly to a stirring pentane solution,
which immediately turned purple. The solutions were then cooled to -78 °C to give purple
crystals of the mono-adduct.
Preparation of WfNPh)( , CH 2 C('CH2 ^') 2 r( ' NSiMe ^ 2 c 6 H i" 1 - 25:
W(NPh)Cl2[(NSiMe 3 ) 2 C6H4] (2.78g, 4.66 mmol) was dissolved in 30 mL of
Et20 and cooled to -78 °C. Two equivalents of ClMgCH2C(CH 3 ) 3 (7.37 mL, 9.32 mmol,
1.27 M soln in Et20) were then added. The reaction was allowed to warm to room
temperature after 30 minutes. After one hour, solvent was removed under reduced
pressure. The solid was extracted with pentane until clear and filtered through a Celite pad.
The solution was concentrated to a total volume of about 10 mL and cooled in an -78 °C
cold bath to yield dark crystals of 25; 2. 19 g (yield 70.1%). Anal. Calc'd for
C28H47N 3 Si 2 W: C, 50.52; H, 7.12; N, 6.31. Found: C, 50.36; H, 7.04; N, 6.14.
Preparation of Wf^h^C^CfCH^Phb^NSiMe^ C^PU l. 26:
W(NPh)Cl 2 [(NSiMe 3 ) 2 C6H4] (2.04 g, 3.42 mmol) was dissolved in 30 mL of
Et 2 and cooled to -78 °C. Two equivalents of ClMgCH 2 C(CH 3 ) 2 Ph (6.55 mL, 6.84
mmol, 1.045 M soln in Et 2 0) were then added. The reaction was allowed to warm to room
temperature after 30 minutes. After one hour, solvent was removed under reduced
pressure. The solid was extracted with pentane until clear and filtered through a Celite pad.
The solution was concentrated to a total volume of about 15 mL and cooled in an -78 °C
cold bath to yield 2.21 g of 26 as a light brown solid. Yield: 82.4%. Anal. Calc'd for
C 38 H4 5 N 3 Si2W: C, 58.23; H, 5.79; N, 5.36. Found: C, 57.95; H, 5.58; N, 5.29.
82
Preparation of WfNPh^CH^WfNSiMe^ CjJU l. 27:
W(NPh)Cl2[(NSiMe3) 2 C6H 4 ] (1.03 g, 1.73 mmol) was dissolved in 20 mL of
Et20 and cooled to -78 °C. Two equivalents of MeLi (2.47 mL, 3.46 mmol, 1.4 M soln in
Et20) were then added. The reaction was allowed to warm to room temperature after 15
minutes. After 30 minutes, solvent was removed under reduced pressure. The solid was
extracted with pentane until clear and filtered through a Celite pad. The solution was
concentrated to a total volume of about 5 mL and cooled in an -78 °C cold bath to yield 680
mg of 27 as a gold-brown solid. Yield: 70.8%. Anal. Calc'd for C20H33N3S12W: C,
43.24; H, 5.99; N, 7.56. Found: C, 42.89; H, 5.94; N, 7.29.
Preparation of WfNPhKCH^CH^^NSiMe^ C^U L 28:
W(NPh)Cl2[(NSiMe3)2C6H4] (1.12 g, 1.88 mmol) was dissolved in 25 mL of
Et20 and cooled to -78 °C. Two equivalents of EtMgCl (1.88 mL, 3.76 mmol, 2.0 M soln
in Et20) were then added. The reaction was allowed to warm to room temperature after 15
minutes. After 30 minutes, solvent was removed under reduced pressure. The solid was
extracted with pentane until clear and filtered through a Celite pad. The solvent was
removed under reduced pressure to yield 0.98 g of 28 as a thick red oil.. Yield: 89.3%.
Preparation of WfNPhVCfoPhbrfNSiMe VbCfiH ^. 29:
W(NPh)Cl2[(NSiMe3)2C6H4] 14 (2.02 g, 3.39 mmol) was dissolved in 25 mL of
Et20 and cooled to -78 °C. Two equivalents of ClMgCH 2 Ph (6.77 mL, 6.77 mmol, 1.0 M
soln. in Et20) were then added. The reaction was allowed to warm to room temperature
after 15 minutes. After 30 minutes, solvent was removed under reduced pressure. The
solid was extracted with pentane until clear and filtered through a Celite pad. The solution
was concentrated to 10 mL and cooled to -78 °C to give 1.47 grams of 29 as a dark solid.
83
Yield: 61.3%. Anal. Calc'd for C32H4iN 3 Si 2 W: C, 54.31; H, 5.84; N, 5.94. Found: C,
53.98; H, 5.61; N, 5.69.
Preparation of WfNPh^CnrCHoCMe^WNSiMe^ bCfiH^ I. 33:
W(NPh)Cl2[(NSiMe3)2C 6 H4] 14 (1.65 g, 2.77 mmol) was dissolved in 25 mL of
Et20 and cooled to -78 °C. One equivalent of ClMgCH2CMe3 (2.31 mL, 2.77 mmol, 1.2
M soln in Et20) was then added. The reaction was allowed to warm to room temperature
after 15 minutes. After 45 minutes, solvent was removed under reduced pressure. The
solid was extracted with pentane until clear and filtered through a Celite pad. The solution
was concentrated to 5 mL and cooled to -78 °C to give 1.09 grams of 33 as a red solid.
Yield: 62.3%. Anal. Calc'd for C23H38N3CIS12W: C, 43.71; H, 6.06; N, 6.65. Found:
C, 43.38; H, 5.81; N, 6.09.
Preparation of W^h^CHCMe ^ ^PMe^WNSiMe^ CAH ^. 3 6 :
In a 200 mL glass tube fitted with a teflon Young's joint,
W(NPh)(CH2CMe3)2[(NSiMe3)2C 6 H 4 ] (1.25 g, 1.87 mmol) was dissolved in 25 mL of
toluene. Five equivalents of PMe3 (.968 mL, 9.35 mmol) were then added and the tube
was sealed. The reaction was then heated to 70 °C for 24 hours. The solution was
transferred to a round-bottom Schlenk were solvent was removed under reduced pressure.
The brown oil was extracted with pentane and the volume of the filtrate was concentrated to
about 15 mL. The solution was cooled to -10 °C to yield 0.83 g of 36 as orange crystals;
yield 66.0%. Anal. Calc'd for C26H4 6 N 3 PSi2W: C, 46.49; H, 6.90; N, 6.26. Found:
C, 46.23; H, 6.81; N, 6.05.
Preparation of WfNPhUCH^Bu)C(Ph)C(Phm(Me3_SiN)9 CAH4[ 38
W(NPh)(CHCMe3)(PMe 3 )[(NSiMe3)2C6H4] 36 (0.21 g, 0.31 mmol) and
diphenylacetylene (0.06 g, 0.34 mmol) were dissolved in 25 mL of pentane. The reaction
84
was then refluxed for 20 hours. Upon cooling, solvent was stripped in vacuo to give a red
oil which appeared pure by l H NMR.
Preparation of WfNPhVHbfPMe V bfTMSTjdaV 39:
Method 1:
In a glass tube with a Teflon Young's joint, W(NPh)(CH 2 CMe 3 ) 2 (TMS2pda) (1.66
g, 2.48 mmol), 25 was dissolved in 25 mL of hexanes. PMe3 (0.64 mL, 6.20 mmol)
was added via syringe. The solution was then placed in liquid nitrogen while a vacuum
was applied. Once the solution was frozen solid under vacuum, the flask was sealed.
Hydrogen gas was then purged through the neck of the flask. Once the neck was purged,
the H 2 hose was wired securely to the flask. The flask was opened until the H 2 reached a
pressure of 10 PSI. The flask was then resealed and the H 2 line removed. The reaction
was then allowed to warm to room temperature. After four hours of stirring, the color of
the solution changed from brown to magenta. Magenta crystals had also precipitated from
solution. The solution was transferred to a Schlenk tube and cooled to -10 °C to give
magenta crystals. The mother liquors were concentrated and cooled to give more of the
same. Total Yield of 39: 1.48 g (87.8%). Anal Calcd for C24H47N3P 2 Si 2 W: C, 42.41;
H, 6.97; N, 6.18. Found: C, 42.18; H, 6.79; N, 6.03.
Method 2:
W(NPh)Cl 2 (TMS 2 pda) (1.08 g, 1.81 mmol), 14 was dissolved in 20 mL of Et 2
and cooled to -78 °C in an isopropanol/dry ice bath. Two equivalents of PMe3 (0.38 mL,
3.62 mmol) were added via syringe. Two equivalents of LiBEt3H (3.62 mL, 3.62 mmol,
1.0 M solution in THF) were added slowly. After warming to room temperature and
stirring for four hours, the solvent was removed under reduced pressure. The solid was
extracted twice with 10 mL of pentane. The brown solution was concentrated to 5 mL and
85
cooled to -10 °C. 0.87 g of a brown-red solid precipitated from solution. l B. NMR
confirmed the formation of 39 with about 15% BEt3 impurity present.
Method 3:
W(NPh)(CHCMe 3 )(PMe3)(TMS 2 pda) 36 (50 mg, 0.07 mmol) was dissolved in
C6D6 in a NMR tube fitted with a teflon Young's joint. One equivalent of PMe3 (7 |iL,
0.07 mmol) was added via microliter syringe. The NMR tube was then fitted with a
Schlenk adapter. The NMR tube was frozen in liquid nitrogen and placed under vacuum.
The tube was then sealed frozen, under vacuum. Hydrogen gas was then purged through
the Schlenk adapter for five minutes. The teflon seal was opened to allow the H2 to fill the
vacuum in the NMR tube. The NMR tube was charged with about 15 PSI of H2. Over a
period of less than 2 hours, complete conversion of 36 to 39 was observed in the *H
NMR.
Preparation of WfNPtOfHbfDPPE'KTMS^pdaV 42:
In a glass tube with a Teflon Young's joint, W(NPh)(CH 2 CMe3)2(TMS2pda) (0.65
g, 0.98 mmol) and DPPE (0.39 g, 0.98 mmol) were dissolved in 30 mL of hexanes. The
solution was then placed in liquid nitrogen while a vacuum was applied. H2 gas was
introduced as described for 39. The reaction was then allowed to warm to room
temperature. After eight hours of stirring, the color of the solution had changed from
brown to purple. Purple solid had also precipitated from solution. The solution was
transferred to a Schlenk tube, concentrated to 10 mL, and cooled to -10 °C to give a purple
solid. Total Yield: 0.71 g (78.2%). Anal. Calcd. for C44H53N3S12P2W: C, 57.08; H,
5.77; N, 4.54. Found: C, 57.33; H, 5.84; N, 4.54.
86
Preparation of WfNPhXr^ -CoHA KPMe^TMSopda). 46:
In a glass tube with a Teflon Young's joint, W(NPh)(H) 2 (PMe3)2(TMS2pda), 39,
(0.64 g, 0.94 mmol) was dissolved in 20 mL of pentane. The solution was then placed in
liquid nitrogen under vacuum. Once the solution was frozen solid under vacuum, the flask
was sealed. Ethylene was purged through the neck of the flask and then the hose was
wired on. The flask was opened to a low pressure of ethylene (2 PSI) for about ten
seconds. Then flask was then resealed and allowed to warm to room temperature. After
12 hours, the color of the solution had lightened. The solution was transferred to a
Schlenk tube and cooled to -10 °C. Purple-brown solid formed and was isolated. The
mother liquors were reduced in volume under reduced pressure to about 5 mL and recooled
to yield more solid. Total yield; 0.59 grams, 89.1%. Anal. Calcd. for C26H49N 3 Si2P2W:
C, 44.25; H, 7.00; N, 5.95. Found: C, 43.91; H, 6.79; N, 5.78.
Polymerization Experiments:
All of the ROMP experiments were carried out under an inert atmosphere in
deolifinated toluene solutions. The reactions were terminated by transfering the mixtures to
stirring methanol with a trace of BHT added to insure against radical reations upon
precipitation. The precipitated polymers were dried in vacuo and analyzed by GPC.
APPENDIX A
TABLES OF SPECTROSCOPIC DATA
Table A-l.lHNMR Data
compound
l,2-[(CH3)3SiNH] 2 C 6 H4 1
l,2-Li 2 [(CH3)3SiN] 2 C6H4 2
l,2-[(CH 3 )2PhSiNH] 2 C6H4 3
l,2-[(CH 3 )Ph 2 SiNH] 2 C6H4 4
4,5-Me 2 -l,2-(Me 3 SiNH) 2 C6H4 6
l,8-(Me3SiNH) 2 CioH 6 7
l,2-Ph[(CH3) 3 SiNH]C 6 H4 8
l,2-0PrNH) 2 C 6 H 4 9
Spectroscopic Data
5, ppm
mult
J, Hz
int
assignt
0.18
S
18
-SiMe3
3.00
br s
2
-NH
6.83
m
2
aromatic
6.89
m
2
0.22
s
18
-SiMe.3
6.59
m
2
aromatic
6.87
m
2
aromatic
0.33
s
12
-SiMe?Ph
3.28
brs
2
-NH
6.69
m
2
aromatic
6.88
m
2
aromatic
7.20
m
6
aromatic
7.57
m
4
aromatic
0.61
s
6
-SiMePh 2
3.57
brs
2
-NH
6.58
m
2
aromatic
6.92
m
2
aromatic
7.18
m
12
aromatic
7.58
m
8
aromatic
0.19
s
18
-SiMe3
2.12
s
6
4,5-Me 2
2.95
br s
2
-NH
6.80
s
2
aromatic
0.17
s
18
-SiMe3
5.38
brs
2
-NH
6.70
d
7
2
p-CioHg
7.19
t
8
2
m-CioHe
7.33
d
7
2
0-C10H6
0.11
s
9
-SiMe 3
4.09
br s
1
-NH
4.43
br s
1
-NH
6.49
d
8
2
aroamtic
6.73
t
8
2
aromatic
6.96
t
8
2
aromatic
7.07
m
3
aromatic
0.98
d
6
12
-CHMe?
3.08
br s
2
-NH
3.32
quin
6
2
-CHMe 2
6.69
m
2
aromatic
6.93
in
2
aromatic
88
89
l,2-[N(H)C(Me) 2 CH 2 CH(Me)N(H)]-
C 6 H 4 10
l,8-[N(H)C(Me) 2 N(H)]CioH 4 11
W(0)Cl 2 [(Me 3 SiN)2C6H4] 13
W(NPh)Cl 2 [(Me 3 SiN) 2 C 6 H 4 ] 14
W(NPh)Cl 2 [(Me 2 PhSiN) 2 C 6 H4] 15
W(NPh)Cl 2 [l,8-(Me3SiN)2CioH 6 ] 18
W(NPh)Cl 2 [4,5-Me 2 -l,2-
(Me 3 SiN) 2 C6H4] 19
0.83
d
6
3
-CHMe
0.89
s
3
-CMe(Me)
1.07
s
3
-CMe(Me)
1.25
dd
6
1
-CHH
1.62
t
6
1
-CHH
2.90
br s
2
-NH
3.17
qd
4
1
-CHMe
6.45
m
2
aromatic
6.80
m
2
aromatic
0.98
s
6
-CMe?
3.42
br s
2
-NH
6.26
d
7
2
aromatic
7.23
d
7
2
aromatic
7.35
t
7
2
aromatic
0.39
s
18
-SiM£3
6.80
m
2
aromatic
6.95
in
2
0.35
s
18
-SiMe 3
6.71
t
8
1
p-NPh-H
6.94
m
2
aromatic
7.01
t
8
2
m-NPh-H
7.14
m
2
aromatic
7.31
d
8
2
o-NPh-H
0.62
s
6
-SiMe?Ph
0.68
s
6
-SiMe 2 Ph
6.62
m
2
aromatic
6.65
t
8
1
p-NPh-H
6.92
t
8
2
m-NPh-H
7.02
to
aromatic
7.47
0.41
s
18
-SiMe 3
6.39
d
7
2
P-C10H6
6.72
t
8
1
p-NPh-H
6.93
d
7
2
0-C10H6
6.98
t
8
2
m-NPh-H
7.13
t
7
2
m-CioH 6
7.48
d
8
2
o-NPh-H
0.41
s
18
-SiMe 3
1.99
s
6
4,5-Me9Ph
6.73
t
8
1
p-NPh-H
7.02
t
8
2
m-NPh-H
7.07
s
2
aromatic
7.35
d
8
2
o-NPh-H
90
W(NPh)(OS02CF3)2[(Me 3 SiN)2C6H 4 ]-
(OEt 2 ) 20
0.32
18 -SiMg3
1.09
t
7
6
-OEt2
3.25
q
7
4
-OEts
6.55
t
8
1
p-NPh-H
7.02
t
8
2
m-NPh-H
7.09
m
2
aromatic
7.30
m
2
aromatic
7.38
d
8
2
o-NPh-H
W(NPh)Cl2(PMe3)[(Me 3 SiN)2C 6 H4]
0.42
s
18
-SiMs3
21
0.79
d
JVh=9
9
-PMe 3
6.63
t
8
1
p-NPh-H
6.83
m
2
aromatic
7.01
IT)
2
aromatic
7.17
t
8
2
m-NPh-H
7.49
d
8
2
o-NPh-H
W(NPh)Cl2(THF)[(Me 3 SiN)2C6H 4 ] 22
0.41
s
18
-SiMe 3
0.92
qnt
3
4
-THF
3.63
t
6
4
-THF
6.62
t
8
1
p-NPh-H
6.85
m
2
aromatic
7.03
m
2
aromatic
7.10
t
8
2
m-NPh-H
7.47
d
8
2
o-NPh-H
W(NPh)Cl 2 (3-Me-py)[(Me3SiN) 2 C6H4]
0.42
s
18
-SiMe 3
23
2.17
s
3
py-Me
6.21
t
2
1
py-5-H
6.33
d
8
1
py-4-H
6.54
m
2
aromatic
6.65
t
11
1
p-NPh-H
6.76
m
2
aromatic
7.18
t
9
2
m-NPh-H
7.61
d
7
2
o-NPh-H
8.72
s
1
py-l-H
8.75
d
6
1
py-6-H
W(NPh)Cl 2 (NCCH3)[(Me3SiN)2C 6 H4]
0.38
s
18
-SiMs3
24
0.49
s
3
-NCCMe
6.67
t
7
1
p-NPh-H
6.93
m
2
aromatic
7.04
t
7
m-NPh-H
7.14
m
2
aromatic
7.34
d
7
2
o-NPh-H
W(NPh)(CH 2 CMe3)2[(Me 3 SiN)2-
0.54
s
18
-SiMS3
C 6 H 4 ] 25
1.00
s
18
-CMe 3
91
W(NPh)(CH 2 CMe2Ph)2[(Me 3 SiN)2-
C 6 H 4 ] 26
W(NPh)(CH3)2[(Me 3 SiN)2C 6 H4l 27
W(NPh)(CH 2 CH3)2[(Me3SiN)2C 6 H4]
28
W(NPh)(CH 2 Ph)2[(Me3SiN)2C 6 H 4 ] 29
2.13
d
10
J 2 WH=H
2
-CH 2 CMe3
2.29
d
10
J 2 WH=H
2
-CH 2 CMe 3
6.83
t
7
1
p-NPh-H
6.86
m
2
aromatic
7.19
t
7
2
m-NPh-H
7.25
m
2
aromatic
7.59
d
7
2
o-NPh-H
0.42
s
18
-SiMe 3
1.37
s
9
-CMe?Ph
1.38
s
9
-CMS2Ph
1.95
d
11
J 2 WH=H
2
-CH2C
2.94
d
11
J 2 WH=H
2
-CH2C
6.83
t
7
1
aromatic
6.94
t
7
2
6.97
m
2
7.01
t
7
4
7.06
t
7
2
7.18
d
7
4
7.19
d
7
2
7.30
m
2
0.31
s
18
-SiMe3
1.12
s
J 2 W-H=6
6
W-Me
6.86
t
8
1
p-NPh-H
7.06
m
2
aromatic
7.11
t
8
2
m-NPh-H
7.32
d
8
2
o-NPh-H
7.35
m
2
aromatic
0.29
s
18
-SiMS3
1.86
s
6
-CH2CH3
1.91
m
2
-CH2CH3
2.31
m
2
-CH2CH3
6.86
t
8
1
p-NPh-H
7.04
m
2
aromatic
7.11
t
8
2
m-NPh-H
7.31
d
8
2
o-NPh-H
7.37
m
2
aromatic
0.09
s
18
-SiMe 3
2.78
s
4
-CH2Ph
6.81
t
8
2
p-CH 2 Ph-H
6.88
t
8
1
p-NPh-H
7.04
to
aromatic
7.19
7.30
d
8
2
o-NPh-H
92
7.37
in
2
aromatic
spectrum taken at +80 °C in C7D8
2.71
m
7
4
— c
W(NPh)Ph2[(Me3SiN)2C 6 H 4 ] 30
0.11
s
18
-SiMe 3
6.82
t
7
2
aromatic
6.86
t
7
1
7.04
t
7
4
7.18
t
7
2
7.21
m
2
7.39
m
2
7.52
d
7
2
7.62
d
7
4
W(NPh)(CH 2 CMe 3 )2-
[(Me2PhSiN) 2 C6H4] 31
0.81
s
12
-SiMe 2 Ph
1.03
s
18
-CH 2 CMe 3
2.04
d
10
Pwh-11
2
-CH 2 CMe 3
2.78
d
10
J 2 WH=H
2
-CH 2 CMe 3
6.59
aromatic
to
7.68
W(NPh)Cl(CH 2 CMe 3 )[(Me 3 SiN) 2 -
0.24
s
9
-SiMe 3
C 6 H 4 ] 33
0.42
s
9
-SiMe 3
1.23
s
9
-CH 2 CMe 3
1.93
d
10
1
-CH9CMe 3
2.08
d
10
1
-CH 2 CMe 3
6.76
t
7
1
p-NPh-H
6.94
to
aromatic
7.24
7.41
d
8
2
o-NPh-H
W(NPh)(CH 2 CMe3)(NMe2)[(Me 3 SiN)2
0.31
s
9
-SiMe 3
C 6 H 4 ] 34
0.46
s
9
-SiMe 3
1.03
s
9
-CH 2 CMe 3
1.33
d
10
1
-CH2CMe 3
2.60
d
10
1
-CH2CMe 3
3.19
s
3
-NMe2
3.68
s
3
-NMS2
6.72
to
aromatic
7.28
W(NPh)(CH 2 C(Me) 2 CH 2 )-
[(Me 3 SiN)2C6H4] 35
-1.70
d
9
2
-CH 2
0.39
s
9
-SiMe 3
0.54
s
3
-CH 2 CMe9-
0.57
s
3
-CH 2 CMe?-
93
1.24
s
9
-SiMe3
2.11
d
9
2
-CH2
6.75
to
aromatic
7.59
W(NPh)(CHCMe3)(PMe3)-
0.38
s
9
-SiM£3
[(Me 3 SiN) 2 C6H4] 36
0.41
s
9
-SiMe 3
0.98
d
2 Jp-h=9
9
-PMS3
1.39
s
9
-CM£3
6.68
to
7.13
9
aromatic
W(NPh)[CH(r-Bu)C(Ph)C(Ph)]-
[(Me 3 SiN)2C6H4] 38
-0.08
s
9
-SiMe 3
0.43
s
9
-SiMe3
1.38
s
9
-r-Bu
2.81
s
2 Jw-h = 8
1
-C-H
6.62
to
aromatic
7.64
W(NPh)(H)2(PMe3)2[(Me3SiN) 2 C 6 H4]
0.79
s
9
-SiMe.3
39
0.81
s
9
-SiMe^
1.04
s
18
-PM§3
6.80
to
aromatic
7.45
9.28
t
J = 38
2
W-H
Spectrum in C7D8 at -50 °C
0.69
s
9
-SiMe 3
0.75
s
9
-SiMe3
0.84
t
J2 P .H=3
18
-PMes
6.74
to
aromatic
7.38
9.00
m
W-H
W(NPh)(H) 2 (PMe2Ph) 2 -
[(Me 3 SiN)2C6H4] 40
0.53
s
18
-SiMe 3
1.22
s
6
-PMe?Ph
6.72
to
aromatic
7.29
9.63
br s
2
W-H
Spectrum in C7D8 at -50 °C
0.53
s
9
-SiMe 3
0.59
s
9
-SiMe3
1.19
t
Jp-H = 4
12
-PMe2Ph
9.56
t
J = 40
2
W-H
94
W(NPh)(H) 2 (PCy3)[(Me3SiN)2C 6 H4]
41
W(NPh)(H)2DPPE[(Me 3 SiN)2C 6 H4]
42
W(NPh)(H)(CH 2 CMe 3 )-
[(Me3SiN)2C6H4] 44
W(NPh)(T!2-C2H4)(PMe3)2-
[(Me 3 SiN)2C 6 H4] 46
spectrum taken at -25 °C
W(NPh)(T! 2 -CH2CHPh)(PMe 3 )2-
[(Me 3 SiN) 2 C 6 H4] 47
0.81
1.04
s
18
-SiMe 3
to
1.93
m's
11
P£*3
6.81
t
7
1
p-Ph-H
6.95
m
2
aromatic
6.99
t
7
2
m-Ph-H
7.18
d
7
2
o-Ph-H
7.47
m
2
aromatic
0.49
s
18
-SiMe 3
2.23
2.42
6.72
m
m
m
2
2
2
PCH2CH2P
PCH2CH2P
aromatic
6.76
m
8
4
aromatic
6.94
m
2
6.98
to
7.18
m
7.69
t
8
4
aromatic
10.33
d
J = 23
1
W-H
10.62
d
J = 23
1
W-H
0.34
0.42
0.94
2.71
3.21
6.79
s
s
s
d
br s
7
9
9
9
1
1
-SiMe 3
-SiMe 3
-CH 2 CMe 3
-CH 2 CMe 3
-CH 2 CMe 3
to
aromatic
7.59
18.48
s
1 J W -H=156
1
W-H
0.37
0.65
1.03
s
s
s
9
9
18
-SiMe 3
-SiMe 3
-PM©
1.91
2.09
6.61
m
m
2
2
C2H4
C2H4
to
aromatic
7.42
0.41
s
18
-SiMe 3
0.86
2.62
2.80
3.87
d
m
m
t
8
3
1
1
1
-PMe3
-QfcCHPh
-OfeGHPh
-CHoCHPh
95
6.41
to aromatic
7.24
Table A-2. 12c NMR Data
96
coumpound
l,8-(Me 3 SiNH)2CioH 6 7
5, ppm
0.80
116.13
mult
s
s
121.22
s
122.21
s
125.99
s
138.15
s
144.60
s
l,2-(iPrNH) 2 C6H 4 9
23.2
44.6
s
s
114.2
s
119.8
s
137.7
s
l,2-[N(H)C(Me) 2 CH 2 CH(Me)N(H)l-
C 6 H 4 10
23.9
26.9
s
s
32.8
s
48.1
s
51.6
s
52.0
s
119.6
s
120.9
s
121.6
s
121.8
s
138.2
s
141.6
s
l,8-[N(H)C(Me) 2 N(H)]Ci H 4 11
28.1
63.8
s
s
105.6
s
111.3
s
117.0
s
127.1
s
135.2
s
140.6
s
WOCl 2 [(Me 3 SiN) 2 C6H4] 13
0.02
121.09
s
s
129.18
s
132.43
W(NPh)Cl 2 [(Me 3 SiN) 2 C 6 H 4 ] 14
0.6
122.0
s
s
126.1
s
128.1
s
128.5
s
128.6
s
130.8
s
Jch, Hz
assignmt
-SiMe 3
aromatic
-NCHMe?
-NCHMe 2
aromatic
NC(Me) 2 N
NC(Me) 2 N
-SiMe 3
-SiMe 3
aromatic
97
W(NPh)Cl2[l,8-(Me3SiN) 2 CioH 6 ] 18
3.13
s
-SiMe 3
121.31
s
aromatic
125.72
s
127.31
s
127.67
s
128.41
s
129.32
s
138.13
s
140.86
s
W(NPh)Cl 2 [4,5-Me 2 -l,2-
(Me 3 SiN)2C 6 H4] 19
1.98
s
-SiMe 3
19.87
s
4,5-Ph-ft
122.32
s
aromatic
124.67
s
126.43
s
128.76
s
133.32
s
142.12
s
148.98
s
W(NPh)Cl2(PMe3)[(Me 3 SiN)2C 6 H4]
21
1.99
s
-SiMe 3
11.64
d
1 Jc-p = 21 -PMe 3
120.94
s
aromatic
122.99
s
127.03
s
127.29
s
128.35
s
145.41
s
W(NPh)Cl2(THF)[(Me 3 SiN)2C6H 4 ] 22
1.50
s
-SiMe 3
25.05
s
THF
70.07
s
THF
120.41
s
aromatic
124.10
s
126.64
s
128.25
s
128.57
s
144.12
s
154.09
s
W(NPh)Cl 2 (3-Me-Py)-
[(Me 3 SiN)2C 6 H4] 23
1.69
s
-SiMe 3
17.70
s
3-Me-py
119.92
s
aromatic
122.61
s
123.16
s
127.03
s
127.91
s
128.15
s
128.55
s
132.81
s
98
137.86
s
147.12
s
148.83
s
152.51
s
W(NPh)(CH 2 CMe3)2[(Me3SiN)2C 6 H4l
4.4
s
-SiMS3
25
34.8
s
-CMS3
38.3
s
-CMe 3
90.8
s
123
-CH 2 CMe 3
118.9
s
aromatic
119.3
s
126.0
s
128.5
s
129.2
s
144.2
s
155.8
s
W(NPh)(CH 2 CMe 2 Ph)2-
4.1
s
-SiM£3
[(Me 3 SiN)2C6H4] 26
32.5
s
-CMe?Ph
35.9
s
-CMe?Ph
44.2
s
-CMe 2 Ph
93.1
s
126
-CH 2 CMe 2 Ph
119.4
s
aromatic
119.8
s
125.5
125.6
126.1
128.2
128.4
129.2
143.8
153.4
155.2
W(NPh)(CH 3 )2[(Me3SiN)2C6H 4 ] 27
2.3
s
-SiMe3
41.2
s
123
-CH3
122.4
s
aromatic
124.8
s
125.2
s
125.8
s
128.7
s
129.8
s
131.2
s
W(NPh)(CH2CH 3 )2[(Me3SiN)2C 6 H 4 ]
28
1.5
s
-SiMe 3
17.4
s
-CH2CH 3
58.4
s
120
-CH2CH3
122.3
123.9
125.0
125.6
99
W(NPh)(CH 2 Ph)2[(Me3SiN)2C 6 H4] 29
W(NPh)Cl(CH 2 CMe 3 )-
[(Me3SiN) 2 C6H 4 ] 33
W(NPh)(CHCMe 3 )(PMe 3 )-
[(Me 3 SiN) 2 C6H4] 36
W(NPh)[CH(f-Bu)C(Ph)C(Ph)]-
[(Me 3 SiN) 2 C 6 H 4 ] 38
128.8
135.1
156.2
2.10
s
66.33
s
123.49
s
123.78
s
125.65
s
126.20
s
126.51
s
127.68
s
128.04
s
128.42
s
128.61
s
128.97
s
154.20
s
1.26
s
2.08
s
35.13
s
36.11
s
80.15
s
121.7
s
122.3
s
123.6
s
126.1
s
127.2
s
128.6
s
132.0
s
136.9
s
155.9
s
3.4
s
4.1
s
16.2
d
34.9
s
45.0
s
117.6
s
119.3
s
122.4
s
123.6
s
124.7
s
128.7
s
148.1
s
277.4
s
1.33
s
2.01
s
33.81
s
38.61
s
-StMe 3
-CH 2 Ph
121
-SiMe 3
-SiMe 3
-CH 2 CMe 3
-CiPiCMes
-CH 2 CMe 3
-SiMe 3
-SiMe 3
-PMe 3
-CMS3
-CMe 3
aromatic
110
aromatic
-CHCMe 3
-SiMe 3
-SiMs 3
-CMs 3
-CMe 3
100
W(NPh)(H) 2 (PMe 3 )2-
[(Me3SiN)2C6H4] 39
W(NPh)(Ti 2 -C 2 H4)(PMe 3 )2-
[(Me 3 SiN)2C6H4] 46
77.10
s
-CH-r-Bu
90.08
s
-CH-r-Bu-CPhCPh
122.08
s
123.09
s
123.42
s
123.92
s
124.68
s
124.99
s
125.38
s
125.91
s
126.01
s
126.46
s
127.00
s
128.20
s
128.62
s
128.78
s
128.93
s
131.97
s
133.15
s
133.31
s
139.91
s
140.03
s
147.08
s
157.83
s
4.92
s
-SiMe3
6.43
s
-SiM£3
15.99
s
-PM£3
115.21
s
aromatic
116.53
s
118.17
s
119.20
s
123.31
s
126.71
s
128.68
s
151.13
s
2.67
s
-SiMS3
6.34
s
-SiMS3
15.78
s
-PMS3
38.13
s 156
122.23
s
123.13
s
124.28
s
125.51
s
127.23
s
128.91
s
129.23
s
129.78
s
158.23
s
101
Table A-3. ^IPNMRData
W(NPh)Cl2(PMe 3 )[(Me3SiN)2C6H4] 21
W(NPh)(CHCMe3)(PMe3)[(Me3SiN)2C 6 H 4 ]36
W(NPh)(CHCMe 3 )(PEt3)[(Me3SiN) 2 C 6 H4]37
W(NPh)(H) 2 (PMe3)2[(Me3SiN) 2 C6H4] 39
W(NPh)(H)2(PMe2Ph)2[(Me3SiN) 2 C6H 4 ] 40
W(NPh)(H)2(PCy3)[(Me 3 SiN)2C 6 H4] 41
W(NPh)(H)2DPPE[(Me 3 SiN)2C 6 H4] 42
W(NPh)0i2-C2H4)(PMe3)2[(Me3SiN) 2 C 6 H4] 46 -23.30
spectrum taken in C7D8 at -40 °C -21.61
-18.22
br s
-2.49
s
J 1 w-P=128
-11.42
br s
-24.46
s
J 1 W_P=188
-17.43
s
J 1 W-P=164
66.71
s
1%-?= 56
30.43
-12.70
d
d
J 2 p.p=83
J 2 P.P=83
-23.30
-21.61
br s
s
J 1 W-P=238
APPENDIX B
TABLES OF CPvYSTALLOGRAPHJC DATA
103
104
Crvstallographic Data for WfNPrACbrfMe^SiNb CgH/l. 14
Table B-l. Crvstallographic data for 14.
A. Crystal data (298 K)
a, A
b, A
c, A
a, deg.
P,deg.
y, deg.
v,A 3
dcalc, g cm" 3 (298 K)
Empirical formula
Formula wt, g
Crystal system
Space group
Z
F(000), electrons
Crystal size (mm 3 )
B. Data collection (298 K)
Radiation, A, (A)
Mode
Scan range
Background
Scan rate, deg. min." 1
28 range, deg.
Range ofhkl
14
10.294(2)
17.859(3)
13.377(3)
104.15(2)
2384.6(8)
1.661
Ci8H 2 7N 3 Si2Cl2W
596.36
Monoclinic
P2i/n
4
1168
0.14x0.21x0.11
Mo-K a , 0.71073
co-scan
Symmetrically over 1.2°
about K a i2 maximum
offset 1.0 and -1.0 in co from
K a i ) 2 m axmuim
3-6
3-55
<
<
-17 <
h
k
I
< 13
< 23
< 17
Total reflections measured
Unique reflections
Absorption coeff. u. (Mo-K a ), mm" 1
Min. & Max. Transmission
C. Structure refinement
S, Goodness-of-fit
Reflections used, I > 2o~(I)
No. of variables
R, wR* (%)
RinL (%)
Max. shift/esd
5770
5300
5.18
0.352, 0.153
1.73
2985
235
5.83%, 6.12%
5.63%
0.0003
105
Table B-l. continued.
min. peak in diff. four, map (e A" 3 ) -2.45
max. peak in diff. four, map (e A" 3 ) 1.56
* Relevant expressions are as follows, where in the footnote F and F c represent,
respectively, the observed and calculated structure-factor amplitudes.
Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2
R = I(IIF I-IF C II)/SF I
wR = [Iw(IF l - IF C I) 2 / IIFqI 2 ] 1 / 2
S = [Zw(IF l-IF c l) 2 /(m-n)] 1 / 2
106
Table B-2: Fractional coordinates and equivalent isotropic^-thermal parameters (A2 )
for the
non-H atoms of compound 14.
Atom
X
v
z
U
W
0.16873(5)
0.21558(3)
0.30838(4)
0.0439(2)
Cll
0.0285(4)
0.1100(3)
0.2519(3)
0.079(2)
C12
0.1131(5)
0.2447(3)
0.1288(3)
0.088(2)
Sil
0.1700(4)
0.1558(2)
0.5550(3)
0.0543(14)
Si2
0.2852(4)
0.3984(3)
0.3248(3)
0.056(2)
Nl
0.1191(10)
0.2080(6)
0.4397(7)
0.051(4)
N2
0.1783(10)
0.3226(6)
0.3385(7)
0.045(4)
N3
0.3280(10)
0.1796(6)
0.3214(8)
0.048(4)
CI
0.0275(13)
0.2686(7)
0.4272(8)
0.044(5)
C2
0.0602(11)
0.3307(7)
0.3721(8)
0.041(4)
C3
-0.0280(12)
0.3933(8)
0.3513(9)
0.049(5)
C4
-0.1391(12)
0.3937(9)
0.3912(10)
0.054(5)
C5
-0.1708(13)
0.3330(9)
0.4451(10)
0.057(6)
C6
-0.0916(13)
0.2718(9)
0.4624(9)
0.057(6)
C7
0.4462(12)
0.1497(8)
0.3062(10)
0.051(5)
C8
0.4420(13)
0.1245(8)
0.2079(11)
0.054(5)
C9
0.556(2)
0.0924(9)
0.1887(13)
0.076(7)
CIO
0.672(2)
0.0858(10)
0.266(2)
0.082(8)
Cll
0.6756(15)
0.1119(10)
0.361(2)
0.089(8)
C12
0.5616(14)
0.1442(9)
0.3827(12)
0.078(7)
C13
0.313(2)
0.0961(10)
0.5456(12)
0.092(8)
C14
0.032(2)
0.0939(9)
0.5689(13)
0.088(8)
C15
0.214(2)
0.2225(10)
0.6625(11)
0.090(7)
C16
0.4484(15)
0.3572(11)
0.3311(14)
0.097(9)
C17
0.216(2)
0.4451(10)
0.1994(11)
0.080(7)
C18
0.298(2)
0.4619(10)
0.4354(11)
0.087(8)
2For anisotropic
atoms, the U value
is U e q, calculated
as U eq = 1/3 Xilj
Uy ai* a;*
Ay where Aj; is
the dot product of the i tn and j tn direc
t space unit cell vectors.
107
Table B-3:
1
2
3
1-2
1-2-3
Cll
W
C12
2.383(4)
82.9(2)
Cll
W
Nl
87.7(3)
Cll
w
N2
146.8(3)
Cll
w
N3
102.9(4)
Cll
w
CI
95.6(3)
C12
w
Nl
2.387(4)
150.5(3)
C12
w
N2
88.9(3)
C12
w
N3
99.8(4)
C12
w
CI
120.5(3)
C12
w
C2
98.2(3)
Nl
w
N2
1.951(11)
83.9(4)
Nl
w
N3
109.5(5)
Nl
w
CI
32.9(4)
Nl
w
C2
61.9(4)
N2
w
N3
1.952(11)
110.2(5)
N2
w
CI
61.4(4)
N2
w
C2
32.4(4)
N3
w
CI
1.730(10)
137.4(4)
N3
w
C2
137.6(4)
CI
w
C2
2.582(13)
31.9(4)
C2
w
Cll
2.582(13)
117.2(3)
Nl
Sil
C13
1.768(10)
108.4(7)
Nl
Sil
C14
109.4(6)
C13
Sil
C14
1.85(2)
107.8(8)
C13
Sil
C15
112.2(8)
C14
Sil
C15
1.84(2)
111.1(8)
C15
Sil
Nl
1.84(2)
107.8(7)
N2
Si2
C16
1.781(12)
106.0(7)
N2
Si2
C17
109.0(6)
C16
Si2
C17
1.82(2)
111.6(8)
C16
Si2
C18
109.2(8)
C17
Si2
C18
1.85(2)
112.7(8)
C18
Si2
N2
1.84(2)
108.0(7)
CI
Nl
W
1.42(2)
98.8(7)
CI
Nl
Sil
123.5(9)
w
Nl
Sil
137.4(7)
C2
N2
W
1.40(2)
99.4(8)
C2
N2
Si2
124.1(9)
W
N2
Si2
136.4(6)
C7
N3
W
1.39(2)
166.2(9)
C2
CI
C6
1.42(2)
118.4(12)
C2
CI
W
74.1(7)
C2
CI
Nl
115.0(12)
C6
CI
W
1.42(2)
151.9(9)
C6
CI
Nl
126.6(12)
W
CI
Nl
48.3(6)
108
Table B-3. continued.
C3
C2
w
1.42(2)
150.1(8)
C3
C2
N2
125.3(11)
C3
C2
CI
119.7(12)
W
C2
N2
48.2(6)
W
C2
CI
74.1(8)
N2
C2
CI
114.9(11)
C4
C3
C2
1.38(2)
118.6(13)
C5
C4
C3
1.38(2)
121.6(13)
C6
C5
C4
1.35(2)
120.9(14)
CI
C6
C5
120.8(13)
C8
C7
C12
1.38(2)
120.5(13)
C8
C7
N3
116.2(10)
C12
C7
N3
1.37(2)
123.3(13)
C9
C8
C7
1.39(2)
118.7(12)
CIO
C9
C8
1.37(2)
121.(2)
Cll
CIO
C9
1.34(3)
120.(2)
C12
Cll
CIO
1.40(2)
120.6(14)
C7
C12
Cll
119.(2)
109
Table B-4
: Anisotropic
thermal parameters^ for the
non-H atoms of
compound 14
Atom
Ull
U22
U33
U12
U13
U23
0.0013(3)
W
0.0429(3)
0.0511(3)
0.0386(3)
0.0116(3)
0.0120(2)
Cll
0.065(2)
0.081(3)
0.091(3)
-0.011(2)
0.018(2)
-0.024(2)
C12
0.128(4)
0.089(3)
0.042(2)
0.028(3)
0.012(2)
0.004(2)
Sil
0.068(3)
0.048(3)
0.045(2)
0.007(2)
0.010(2)
0.010(2)
Si2
0.045(2)
0.064(3)
0.060(2)
-0.005(2)
0.019(2)
0.002(2)
Nl
0.058(6)
0.054(8)
0.044(6)
0.007(6)
0.019(5)
0.006(5)
N2
0.064(7)
0.038(6)
0.043(5)
0.007(5)
0.029(5)
0.003(5)
N3
0.048(7)
0.046(7)
0.053(6)
0.012(5)
0.020(5)
-0.014(5)
CI
0.044(7)
0.053(10)
0.033(6)
0.010(6)
0.004(5)
-0.005(5)
C2
0.038(6)
0.059(9)
0.031(5)
0.006(6)
0.016(5)
0.002(6)
C3
0.040(7)
0.058(9)
0.049(7)
-0.001(7)
0.013(6)
0.009(7)
C4
0.038(7)
0.075(11)
0.051(7)
0.005(7)
0.014(6)
-0.008(7)
C5
0.042(7)
0.085(12)
0.046(7)
-0.004(8)
0.016(6)
-0.003(8)
C6
0.051(8)
0.077(12)
0.041(7)
-0.010(8)
0.008(6)
0.009(7)
C7
0.040(7)
0.045(9)
0.068(8)
-0.006(6)
0.018(6)
-0.013(7)
C8
0.046(8)
0.049(9)
0.066(8)
0.009(7)
0.014(7)
0.005(7)
C9
0.089(12)
0.070(12)
0.088(11)
0.013(10)
0.056(10)
0.003(9)
CIO
0.051(10)
0.065(12)
0.14(2)
0.007(9)
0.033(11)
0.017(12)
Cll
0.039(9)
0.079(14)
0.13(2)
0.003(8)
-0.020(10)
-0.009(12)
C12
0.058(9)
0.090(13)
0.071(9)
0.019(9)
-0.014(8)
-0.029(9)
C13
0.113(15)
0.093(15)
0.073(11)
0.038(12)
0.025(10)
0.019(10)
C14
0.099(13)
0.054(11)
0.109(13)
-0.003(10)
0.019(11)
0.038(10)
C15
0.120(14)
0.086(13)
0.053(8)
0.018(12)
-0.003(9)
-0.017(9)
C16
0.064(11)
0.10(2)
0.13(2)
0.025(11)
0.037(10)
0.026(13)
C17
0.075(11)
0.085(14)
0.082(11)
-0.017(10)
0.025(9)
-0.001(10)
C18
0.085(12)
0.084(13)
0.085(12)
-0.021(10)
0.010(9)
0.000(10)
2 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expression
exp[-27c 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)]
110
Table B-5: Fractional coordinates and isotropic-thermal parameters (A2)
for the H atoms
of c
impound 14.
Atom
X
V
z
U
H3
-0.0103(12)
0.4344(8)
0.3102(9)
0.08
H4
-0.1961(12)
0.4370(9)
0.3814(10)
0.08
H5
-0.2502(13)
0.3346(9)
0.4706(10)
0.08
H6
-0.1163(13)
0.2300(9)
0.4988(9)
0.08
H8
0.3616(13)
0.1291(8)
0.1539(11)
0.08
H9
0.555(2)
0.0746(9)
0.1207(13)
0.08
H10
0.750(2)
0.0624(10)
0.252(2)
0.08
Hll
0.7571(15)
0.1085(10)
0.414(2)
0.08
H12
0.5645(14)
0.1622(9)
0.4508(12)
0.08
H13a
0.342(2)
0.0673(10)
0.6077(12)
0.08
H13b
0.385(2)
0.1270(10)
0.5363(12)
0.08
H13c
0.286(2)
0.0628(10)
0.4878(12)
0.08
H14a
0.060(2)
0.0656(9)
0.6315(13)
0.08
H14b
0.010(2)
0.0603(9)
0.5112(13)
0.08
H14c
-0.045(2)
0.1236(9)
0.5712(13)
0.08
H15a
0.242(2)
0.1955(10)
0.7262(11)
0.08
H15b
0.138(2)
0.2527(10)
0.6640(11)
0.08
H15c
0.286(2)
0.2541(10)
0.6534(11)
0.08
H16a
0.5103(15)
0.3958(11)
0.3241(14)
0.08
H16b
0.4410(15)
0.3215(11)
0.2764(14)
0.08
H16c
0.4800(15)
0.3324(11)
0.3963(14)
0.08
H17a
0.274(2)
0.4860(10)
0.1915(11)
0.08
H17b
0.128(2)
0.4636(10)
0.1972(11)
0.08
H17c
0.212(2)
0.4097(10)
0.1446(11)
0.08
H18a
0.355(2)
0.5033(10)
0.4297(11)
0.08
H18b
0.335(2)
0.4353(10)
0.4983(11)
0.08
H18c
0.210(2)
0.4803(10)
0.4359(11)
0.08
Ill
1
2
3
1-2
1-2-3
H3
C3
C4
0.96(2)
121.(2)
H3
C3
C2
120.7(15)
H4
C4
C5
0.96(2)
119.(2)
H4
C4
C3
119.(2)
H5
C5
C6
0.96(2)
120.(2)
H5
C5
C4
120.(2)
H6
C6
CI
0.96(2)
120.(2)
H6
C6
C5
120.(2)
H8
C8
C9
0.96(2)
121.(2)
H8
C8
C7
121.(2)
H9
C9
CIO
0.96(3)
120.(2)
H9
C9
C8
120.(2)
H10
CIO
Cll
0.96(3)
120.(2)
HIO
CIO
C9
120.(2)
Hll
Cll
C12
0.96(2)
120.(2)
Hll
Cll
CIO
120.(2)
H12
C12
C7
0.96(2)
120.(2)
H12
C12
Cll
120.(2)
H13a
C13
H13b
0.96(2)
109.(2)
H13a
C13
H13c
109.(2)
H13a
C13
Sil
109.(2)
H13b
C13
H13c
0.96(3)
109.(2)
H13b
C13
Sil
109.(2)
H13c
C13
Sil
0.96(2)
109.(2)
H14a
C14
H14b
0.96(2)
109.(2)
H14a
C14
H14c
109.(2)
H14a
C14
Sil
109.5(15)
H14b
C14
H14c
0.96(2)
109.(2)
H14b
C14
Sil
109.(2)
H14c
C14
Sil
0.96(2)
109.(2)
H15a
C15
H15b
0.96(2)
109.(2)
H15a
C15
H15c
109.(2)
H15a
C15
Sil
109.(2)
H15b
C15
H15c
0.96(3)
109.(2)
H15b
C15
Sil
109.5(14)
H15c
C15
Sil
0.96(3)
110.(2)
H16a
C16
H16b
0.96(3)
109.(2)
H16a
C16
HI 6c
109.(2)
H16a
C16
Si2
109.(2)
HI 6b
C16
H16c
0.96(3)
109.(2)
H16b
C16
Si2
109.5(14)
HI 6c
C16
Si2
0.96(3)
109.(2)
H17a
C17
H17b
0.96(2)
109.(2)
H17a
C17
H17c
109.(2)
H17a
C17
Si2
109.5(13)
H17b
C17
HI 7c
0.96(2)
109.(2)
112
Table B-6 continued.
H17b
C17
Si2
H17c
C17
Si2
H18a
C18
H18b
H18a
C18
H18c
H18a
C18
Si2
H18b
C18
H18c
H18b
C18
Si2
H18c
C18
Si2
109.(2)
0.96(2) 109.(2)
0.96(2) 109.(2)
109.(2)
109.(2)
0.96(2) 109.(2)
109.(2)
0.96(2) 109.5(14)
113
Crvstallographic Data for WfNPh^CbiTMe^rfMe^ SiNbCgFLil. 21
Table B-7. Crystallographic Data.
A. Crystal data (298 K)
a, A
b, A
c, A
21
9.562 (1)
10.277 (1)
14.920 (2)
a, deg.
82.15 (1)
p\ deg.
80.18 (1)
y, deg.
80.41 (1)
v,A 3
1415.6 (3)
J ca ic,gcm- 3 (298K)
Empirical formula
Formula wt, g
Crystal system
Space group
Z
F(000), electrons
1.578
C2iH 36 N 3 PCl2W
672.43
Triclinic
P-1
2
668.0
Crystal size (mm 3 )
0.25x0.10x0.09
B. Data collection (298 K)
Radiation, X (A)
Mo-K a , 0.71073
Mode
u)- scan
Scan range
Symmetrically over 1.2° about
Kai,2 maximum
Background
offset 1.0 and -1.0 in co from
Kai,2 maxuTmrn
Scan rate, deg. min." 1
3-6
28 range, deg.
Range ofhkl
3-45
< h < 11
-12 < k < 12
-17 < I < 17
Total reflections measured
Unique reflections
5312
4981
Absorption coeff. |i (Mo-K a ), cm" 1
Min. & Max. Transmission
4.42
0.34906, 0.75350
C. Structure refinement
S, Goodness-of-fit
1.2810
Reflections used, I > 2a(I)
No. of variables
R, wR* (%)
Rint. (%)
Max. shift/esd
4224
271
0.0408, 0.0426
0.0149
0.0005
114
115
Supplementary Table 1 continued.
min. peak in diff. four, map (e A" 3 ) - 1 .280
max. peak in diff. four, map (e A" 3 ) 0.823
* Relevant expressions are as follows, where in the footnote F and F c represent,
respectively, the observed and calculated structure-factor amplitudes.
Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2
R = I(IIF l-IF c ll)/IIFol
wR = [Iw(IF l - IF C I) 2 / I IFqI 2 ] 1 / 2
S^tSwOFol-IFcl^/tm-n)] 1 / 2
116
Table B-8: Fractional coordinates and equivalent isotropic a thermal parameters (A^) for
the non-H atoms of compound 21.
Atom
w
0.12434(3)
Cll
0.3444(2)
C12
0.1471(2)
P
0.0480(3)
Sil
0.1579(2)
Si2
-0.1611(2)
Nl
0.0590(5)
N2
-0.0803(5)
N3
0.2226(6)
CI
-0.0875(6)
C2
-0.1635(7)
C3
-0.3100(8)
C4
-0.3805(8)
C5
-0.3075(8)
C6
-0.1616(8)
C7
0.3211(7)
C8
0.3295(10)
C9
0.4230(12)
CIO
0.5067(11)
Cll
0.4990(11)
C12
0.4076(9)
C13
0.0412(9)
C14
0.3150(8)
C15
0.2179(9)
C16
-0.3014(9)
C17
-0.0214(9)
C18
-0.2416(10)
C19
0.0354(13)
C20
0.1727(11)
C21
-0.1202(11)
0.18104(3)
0.2738(2)
0.2147(2)
0.4471(2)
0.1751(2)
0.0550(2)
0.2082(6)
0.1576(6)
0.0219(6)
0.2593(7)
0.2302(7)
0.2741(8)
0.3426(9)
0.3702(8)
0.3299(8)
-0.0877(8)
-0.2036(10)
-0.3135(11)
-0.3108(13)
-0.1985(14)
-0.0843(11)
0.1159(9)
0.0453(9)
0.3319(9)
-0.0258(10)
-0.0765(9)
0.1603(10)
0.5472(10)
0.5247(10)
0.4987(12)
0.23475(2)
0.23418(14)
0.06792(12)
0.1953(2)
0.46064(14)
0.18439(14)
0.3671(3)
0.2443(4)
0.2314(4)
0.3790(5)
0.3112(5)
0.3181(5)
0.3898(7)
0.4552(6)
0.4507(5)
0.2074(5)
0.2659(7)
0.2402(10)
0.1580(10)
0.1002(8)
0.1239(6)
0.5674(5)
0.4378(6)
0.4779(6)
0.2649(6)
0.1388(6)
0.0909(6)
0.2883(7)
0.1071(7)
0.1528(9)
U
0.03253(10)
0.0566(8)
0.0544(8)
0.0531(8)
0.0414(7)
0.0453(8)
0.034(2)
0.034(2)
0.038(2)
0.034(2)
0.038(2)
0.048(3)
0.063(4)
0.056(3)
0.047(3)
0.044(3)
0.073(4)
0.099(6)
0.091(6)
0.096(5)
0.075(4)
0.058(3)
0.063(4)
0.067(4)
0.065(4)
0.059(3)
0.069(4)
0.090(5)
0.081(4)
0.106(6)
£For anisotropic atoms, the U value is U e q, calculated as U eq = 1/3 Ej£j Ujj ai* aj* Ay
where Ajj is the dot product of the i th and j th direct space unit cell vectors.
117
Table B-9: Bond Lengths (A) and Angles (°) for the non-H atoms of compound 21.
1-2 1-2-3
Cll
W
C12
2.449(2)
92.43(7)
Cll
w
P
75.86(7)
Cll
w
Nl
91.2(2)
Cll
w
N2
163.5(2)
Cll
w
N3
90.4(2)
Cll
w
CI
111.4(2)
C12
w
P
2.443(2)
75.70(7)
C12
w
Nl
161.0(2)
C12
w
N2
90.7(2)
C12
w
N3
91.2(2)
C12
w
CI
135.07(14)
C12
w
C2
109.9(2)
P
w
Nl
2.720(2)
87.2(2)
P
w
N2
89.2(2)
P
w
N3
160.3(2)
P
w
CI
74.25(14)
P
w
C2
75.3(2)
Nl
vv
N2
2.010(5)
80.8(2)
Nl
w
N3
107.4(2)
Nl
w
CI
28.3(2)
Nl
w
C2
56.8(2)
N2
w
N3
1.990(5)
105.8(3)
N2
w
CI
56.5(2)
N2
w
C2
27.9(2)
N3
w
CI
1.747(6)
124.6(2)
N3
w
C2
123.6(2)
CI
w
C2
2.797(6)
29.7(2)
C2
w
Cll
2.785(6)
137.4(2)
Nl
Sil
1.781(6)
CI
Nl
W
1.402(8)
108.8(4)
CI
Nl
Sil
121.6(4)
w
Nl
Sil
129.6(3)
C2
N2
W
1.387(9)
109.8(5)
C7
N3
w
1.388(9)
164.3(5)
C2
CI
C6
1.430(11)
119.7(6)
C2
CI
w
74.7(4)
C2
CI
Nl
114.4(6)
C6
CI
W
1.399(10)
160.3(6)
C6
CI
Nl
125.9(7)
W
CI
Nl
42.8(3)
C3
C2
W
1.389(9)
159.9(5)
C3
C2
N2
126.3(7)
C3
C2
CI
118.8(6)
W
C2
N2
42.2(3)
w
C2
CI
75.6(3)
N2
C2
CI
114.9(5)
118
Table B-9 continued.
C4
C3
C2
1.377(12)
120.3(8)
C5
C4
C3
1.376(14)
120.9(7)
C6
C5
C4
1.380(11)
120.9(8)
CI
C6
C5
119.4(8)
C8
C7
C12
1.377(12)
118.9(8)
C8
C7
N3
120.2(7)
C12
C7
N3
1.372(11)
120.8(7)
C9
C8
C7
1.373(14)
120.0(9)
CIO
C9
C8
1.35(2)
121.2(11)
Cll
CIO
C9
1.34(2)
119.4(11)
C12
Cll
CIO
1.39(2)
121.4(10)
C7
C12
Cll
119.1(9)
119
Table B-10: Anisotropic thermal parameters a for the non-H atoms of compound 21.
Atom Ull U22 U33 U12 U13 U23
W
Cll
C12
P
Sil
Si2
Nl
N2
N3
CI
C2
C3
C4
C5
C6
C7
C8
C9
CIO
Cll
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
0.0293(2)
0.0403(10)
0.0601(12)
0.0638(14)
0.0376(10)
0.0453(12)
0.030(3)
0.033(3)
0.038(3)
0.025(3)
0.030(3)
0.037(4)
0.032(4)
0.050(5)
0.042(4)
0.029(4)
0.072(6)
0.087(8)
0.062(7)
0.066(7)
0.064(6)
0.067(5)
0.042(4)
0.062(5)
0.058(5)
0.070(6)
0.068(6)
0.151(11)
0.107(8)
0.078(7)
0.0372(2)
0.0696(15)
0.0670(14)
0.0431(13)
0.0516(13)
0.0555(14)
0.040(3)
0.036(3)
0.041(4)
0.039(4)
0.040(4)
0.054(5)
0.063(6)
0.052(5)
0.053(5)
0.048(5)
0.063(7)
0.056(7)
0.083(9)
0.139(12)
0.101(8)
0.067(6)
0.083(7)
0.078(7)
0.078(7)
0.054(5)
0.092(8)
0.050(6)
0.064(7)
0.086(9)
0.0298(2)
0.0610(13)
0.0324(10)
0.0489(12)
0.0384(11)
0.0396(11)
0.031(3)
0.033(3)
0.033(3)
0.040(4)
0.042(4)
0.054(5)
0.091(7)
0.062(5)
0.046(4)
0.053(5)
0.075(7)
0.135(11)
0.128(11)
0.071(7)
0.044(5)
0.043(5)
0.060(5)
0.074(6)
0.069(6)
0.059(5)
0.051(5)
0.063(6)
0.068(6)
0.140(11)
-0.00271(10)
-0.0191(10)
-0.0052(10)
-0.0067(10)
-0.0085(9)
-0.0103(10)
-0.007(2)
-0.000(2)
-0.003(3)
-0.006(3)
-0.002(3)
-0.003(4)
0.011(4)
0.001(4)
-0.006(4)
0.001(3)
0.000(5)
0.022(6)
0.028(6)
0.029(7)
0.019(5)
-0.013(5)
0.005(4)
-0.031(5)
-0.032(5)
-0.007(4)
-0.003(5)
-0.025(6)
-0.035(6)
0.005(6)
-0.00254(10)
-0.0036(9)
-0.0014(8)
-0.0066(10)
-0.0094(8)
-0.0135(9)
-0.003(2)
-0.009(2)
-0.004(2)
-0.002(3)
-0.003(3)
-0.011(3)
-0.006(4)
0.003(4)
-0.002(3)
-0.008(3)
0.009(5)
-0.004(8)
-0.025(7)
0.009(5)
0.002(4)
-0.012(4)
-0.012(4)
-0.011(5)
-0.016(4)
-0.017(4)
-0.032(4)
0.014(6)
-0.003(6)
-0.036(7)
-0.00437
-0.0024(
-0.0048(
0.0026(
-0.0097(
-0.0092(
-0.003(3
-0.003(3
-0.005(3
-0.006(3
-0.006(3
-0.011(4
-0.024(5
-0.016(4
-0.013(4
-0.009(4
-0.009(5
0.000(7
-0.043(8
-0.045(8
-0.008(5
-0.009(4
-0.009(5
-0.026(5
-0.007(5
-0.022(4
-0.004(5
-0.009(5
0.016(5
0.037(8
11
1)
0)
0)
0)
0)
2 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expressk
exp[-27t 2 (h 2 a* 2 Ul 1 + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)]
120
Table B-l 1: Fractional coordinates and isotropic thermal parameters (A 2) for the H atoms of
compound 21.
Atom
H3
-0.3623(8)
H4
-0.4819(8)
H5
-0.3587(8)
H6
-0.1115(8)
H8
0.2700(10)
H9
0.4288(12)
H10
0.5713(11)
Hll
0.5578(11)
H12
0.4051(9)
H13a
0.0954(9)
H13b
0.0082(9)
H13c
-0.0397(9)
H14a
0.3668(8)
H14b
0.3767(8)
H14c
0.2829(8)
H15a
0.2715(9)
H15b
0.1357(9)
H15c
0.2775(9)
H16a
-0.3437(9)
H16b
-0.3743(9)
H16c
-0.2585(9)
H17a
-0.0636(9)
H17b
0.0199(9)
H17c
0.0520(9)
H18a
-0.2849(10)
H18b
-0.1685(10)
H18c
-0.3134(10)
H19a
-0.0291(13)
H19b
0.0001(13)
H19c
0.1286(13)
H20a
0.2676(11)
H20b
0.1448(11)
H20c
0.1718(11)
H21a
-0.1953(11)
H21b
-0.1140(11)
H21c
-0.1409(11)
u
0.2566(8)
0.2726(5)
1.08
0.3716(9)
0.3941(7)
1.08
0.4179(8)
0.5047(6)
1.08
0.3502(8)
0.4964(5)
1.08
-0.2076(10)
0.3247(7)
1.08
-0.3936(11)
0.2817(10)
1.08
-0.3884(13)
0.1408(10)
1.08
-0.1971(14)
0.0412(8)
1.08
-0.0041(11)
0.0825(6)
1.08
0.0983(9)
0.6174(5)
1.08
0.0360(9)
0.5586(5)
1.08
0.1830(9)
0.5809(5)
1.08
0.0288(9)
0.4889(6)
1.08
0.0748(9)
0.3837(6)
1.08
-0.0351(9)
0.4289(6)
1.08
0.3157(9)
0.5282(6)
1.08
0.3978(9)
0.4911(6)
1.08
0.3631(9)
0.4233(6)
1.08
-0.0800(10)
0.2325(6)
1.08
0.0413(10)
0.2900(6)
1.08
-0.0801(10)
0.3135(6)
1.08
-0.1313(9)
0.1070(6)
1.08
-0.1298(9)
0.1885(6)
1.08
-0.0366(9)
0.0974(6)
1.08
0.1070(10)
0.0585(6)
1.08
0.2008(10)
0.0495(6)
1.08
0.2282(10)
0.1158(6)
1.08
0.5146(10)
0.3399(7)
1.08
0.6379(10)
0.2688(7)
1.08
0.5422(10)
0.3055(7)
1.08
0.5033(10)
0.1231(7)
1.08
0.6192(10)
0.1018(7)
1.08
0.4926(10)
0.0498(7)
1.08
0.4626(12)
0.1950(9)
1.08
0.4673(12)
0.0943(9)
1.08
0.5939(12)
0.1463(9)
1.08
121
Table B-12: Bond Lengths (A) and Angles (°) of the H atoms of compound 21.
1-2
1-2-3
H3
C3
C4
0.960(12)
119.9(8)
H3
C3
C2
119.8(8)
H4
C4
C5
0.960(11)
119.6(11)
H4
C4
C3
119.6(11)
H5
C5
C6
0.960(12)
119.6(10)
H5
C5
C4
119.5(9)
H6
C6
CI
0.960(12)
120.3(8)
H6
C6
C5
120.3(9)
H8
C8
C9
0.960(13)
120.0(11)
H8
C8
C7
120.0(10)
H9
C9
CIO
0.96(2)
119.4(13)
H9
C9
C8
119.4(14)
H10
CIO
Cll
0.96(2)
120.3(14)
H10
CIO
C9
120.3(14)
Hll
Cll
C12
0.960(15)
119.2(14)
Hll
Cll
CIO
119.3(15)
H12
C12
C7
0.960(14)
120.4(11)
H12
C12
Cll
120.5(10)
H13a
C13
H13b
0.960(12)
109.5(11)
H13a
C13
HI 3c
109.5(11)
H13b
C13
H13c
0.960(14)
109.5(11)
H14a
C14
HI 4b
0.960(13)
109.5(11)
H14a
C14
H14c
109.5(12)
H14b
C14
H14c
0.960(11)
109.5(12)
H15a
C15
HI 5b
0.960(14)
109.5(12)
H15a
C15
HI 5c
109.5(12)
H15b
CI 5
HI 5c
0.960(12)
109.5(11)
H16a
C16
HI 6b
0.960(15)
109.5(11)
H16a
C16
H16c
109.5(12)
H16b
C16
H16c
0.960(12)
109.5(12)
H17a
C17
HI 7b
0.960(14)
109.5(11)
H17a
C17
H17c
109.5(11)
H17b
C17
H17c
0.960(12)
109.5(11)
H18a
C18
HI 8b
0.96(2)
109.5(12)
H18a
C18
HI 8c
109.5(12)
H18b
C18
HI 8c
0.960(13)
109.5(13)
H19a
C19
H19b
0.960(14)
109.5(13)
H19a
C19
H19c
109.5(13)
H19b
CI 9
HI 9c
0.960(13)
109.5(15)
H20a
C20
H20b
0.96(2)
109.5(15)
H20a
C20
H20c
109.5(13)
H20b
C20
H20c
0.960(14)
109.5(12)
H21a
C21
H21b
0.96(2)
109.(2)
H21a
C21
H21c
109.5(14)
H21b
C21
H21c
0.96(2)
109.(2)
122
123
Crystallogranhic data for WfNPh^rCHCMft^ CPMp^r^Mp.^iN^orgHlIJ^.
Table B-13: Crvstallographic data for 36
A. Crystal data (298 K)
a, A
b, A
c, A
a, deg.
Meg.
% deg.
v,A 3
dado g cm" 3 (298 K)
Empirical formula
Formula wt, g
Crystal system
Space group
Z
F(000), electrons
Crystal size (mm 3 )
B. Data collection (298 K)
Radiation, X (A)
Mode
Scan range
Background
Scan rate, deg. min." 1
29 range, deg.
Range ofhkl
Total reflections measured
Unique reflections
Absorption coeff. \i (Mo-K a ), mm" 1
Min. & Max. Transmission
C. Structure refinement
S, Goodness-of-fit
Reflections used, I > 2a(I)
No. of variables
R, wR* (%)
Rim. (%)
Max. shift/esd
36
16.116(3)
11.340(2)
17.960(4)
106.28(2)
3151(1)
1.416
C 2 6H46N 3 Si2PW
671.66
Monoclinic
P2i/c
4
1360
0.38x0.21x0.13
Mo-K a , 0.71073
co-scan
Symmetrically over 1.2°
about K a i ^ maximum
offset 1.0 and -1.0 in co from
K a i 2 maximum
3-6
3-50
<
<
-19 <
6099
5563
3.81
0.486, 0.618
1.15
3209
298
5.25%,
4.00%
0.0001
h
k
I
<
<
<
19
12
19
5.10%
124
Table B-13 continued.
min. peak in diff. four, map (e A" 3 ) -1.10
max. peak in diff. four, map (e A" 3 ) 1.40
* Relevant expressions are as follows, where in the footnote F and F c represent,
respectively, the observed and calculated structure-factor amplitudes.
Function minimized was w(IF l - IF C I) 2 , where w= (a(F))" 2
R = £(IIFol-IF c ll)/SFol
wR = Ew(IFol - IF C I) 2 / IIFol 2 ] 1 / 2
S = [Ew(IF l-IF c l) 2 /(m-n)] 1 / 2
125
Table B-14: Fractional coordinates and equivalent isotropic^-thermal parameters
(A =) for the non-H atoms of compound 36
Atom
w
-0.25717(3)
PI
-0.3548(2)
Si2
-0.1756(3)
Si3
-0.1715(3)
Nl
-0.3349(6)
N2
-0.2221(6)
N3
-0.2474(6)
CI
-0.4058(8)
C2
-0.4478(8)
C3
-0.5195(9)
C4
-0.5471(10)
C5
-0.5086(10)
C6
-0.4371(9)
C7
-0.2633(8)
C8
-0.2879(9)
C9
-0.3293(9)
CIO
-0.3502(10)
Cll
-0.3261(9)
C12
-0.2796(8)
C13
-0.1697(8)
C14
-0.1401(8)
C15
-0.1472(11)
C16
-0.1978(10)
C17
-0.0464(9)
C18
-0.1271(9)
C19
-0.2553(8)
C20
-0.0896(9)
C21
-0.1049(10)
C22
-0.1015(10)
C23
-0.2206(9)
C24
-0.4488(8)
C25
-0.3214(9)
C26
-0.4003(8)
&For anisotropic
atoms, the U vali
Ajj where Ajj is
the dot product o
0.13867(5)
0.2116(3)
0.0067(4)
-0.0438(4)
0.2095(9)
0.0012(8)
-0.0029(9)
0.2263(12)
0.1309(14)
0.149(2)
0.263(2)
0.354(2)
0.3402(12)
-0.0999(11)
-0.2024(13)
-0.2908(12)
-0.2888(13)
-0.1941(14)
-0.1003(11)
0.2529(11)
0.3780(13)
0.4449(13)
0.4429(13)
0.3786(14)
0.1518(13)
-0.0145(13)
-0.1054(14)
0.0828(14)
-0.156(2)
-0.1051(14)
0.1170(13)
0.2068(14)
0.3587(12)
0.03328(3)
0.1098(2
-0.1059(2
0.1953(2
-0.0450(6
-0.0297(5
0.1078(6
-0.1088(7
-0.1508(8
-0.2139(8
-0.2342(9
-0.1924(8
-0.1294(8
-0.0138(7
-0.0601(8
-0.0398(9
0.0297(9
0.0771(9
0.0602(7
0.0663(7
0.0621(8
0.1341(9
-0.0079(9
0.0597(9
-0.1067(7
-0.2021(7
-0.0931(9
0.2422(8
0.1742(9
0.2697(8
0.0819(9
0.2147(7
0.0893(8
U
0.0334(2)
0.0443(14)
0.046(2)
0.050(2)
0.040(4)
0.034(4)
0.043(4)
0.040(5)
0.053(6)
0.074(7)
0.073(8)
0.064(6)
0.054(6)
0.037(5)
0.055(6)
0.057(7)
0.062(7)
0.061(7)
0.039(5)
0.043(5)
0.052(6)
0.089(9)
0.081(8)
0.081(8)
0.066(6)
0.055(6)
0.089(8)
0.080(7)
0.108(9)
0.083(8)
0.072(7)
0.071(7)
0.058(6)
Ts.! Q'^ Q '*
126
1
2
3
1-2
1-2-3
PI
W
Nl
2.502(4)
82.8(4)
PI
W
N2
148.1(3)
PI
w
N3
81.2(3)
Nl
w
N2
1.789(9)
98.4(4)
Nl
w
N3
140.1(4)
Nl
w
C13
103.6(5)
N2
w
N3
2.095(10)
77.8(4)
N2
w
C13
113.0(5)
N3
w
C13
2.067(10)
114.6(4)
C13
w
PI
1.884(13)
97.5(4)
C24
PI
C25
1.809(13)
104.6(7)
C24
PI
C26
103.2(6)
C24
PI
W
105.0(5)
C25
PI
C26
1.808(13)
102.9(7)
C25
PI
W
120.9(5)
C26
PI
W
1.818(14)
118.2(5)
N2
Si2
C18
1.736(11)
108.6(6)
N2
Si2
C19
113.0(6)
C18
Si2
C19
1.82(2)
107.2(6)
C18
Si2
C20
108.3(7)
C19
Si2
C20
1.856(11)
109.1(7)
C20
Si2
N2
1.85(2)
110.6(6)
N3
Si3
C21
1.761(9)
111.8(6)
N3
Si3
C22
108.4(6)
C21
Si3
C22
1.85(2)
109.0(7)
C21
Si3
C23
105.7(7)
C22
Si3
C23
1.81(2)
107.5(8)
C23
Si3
N3
1.87(2)
114.2(6)
CI
Nl
W
1.387(14)
160.8(9)
C7
N2
w
1.39(2)
106.6(8)
C7
N2
Si2
121.8(8)
W
N2
Si2
129.8(5)
C12
N3
W
1.40(2)
105.6(7)
C12
N3
Si3
112.4(8)
W
N3
Si3
133.6(6)
C2
CI
C6
1.38(2)
119.6(11)
C2
CI
Nl
120.5(11)
C6
CI
Nl
1.40(2)
119.9(11)
C3
C2
CI
1.39(2)
119.9(14)
C4
C3
C2
1.39(3)
119.(2)
C5
C4
C3
1.33(2)
121.1(13)
C6
C5
C4
1.38(2)
122.(2)
CI
C6
C5
118.8(13)
C8
C7
C12
1.42(2)
116.7(12)
C8
C7
N2
128.6(13)
C12
C7
N2
1.43(2)
114.6(11)
127
Table B-15 continued
C9
C8
C7
1.31(2)
122.9(15)
CIO
C9
C8
1.38(2)
120.7(14)
Cll
CIO
C9
1.36(2)
118.7(15)
C12
Cll
CIO
1.38(2)
123.(2)
N3
C12
C7
115.6(12)
N3
C12
Cll
127.1(13)
C7
C12
Cll
117.3(12)
C14
C13
W
1.50(2)
148.4(9)
C15
C14
C16
1.53(2)
106.5(12)
C15
C14
C17
109.3(11)
C15
C14
C13
109.0(12)
C16
C14
C17
1.53(2)
110.8(13)
C16
C14
C13
111.6(10)
C17
C14
C13
1.52(2)
109.7(12)
128
Table B-16: Anisotropic thermal parameters^ for the non-H atoms of compound 36.
Atom
Ull
w
0.0377(3)
PI
0.048(2)
Si2
0.050(2)
Si3
0.050(2)
Nl
0.043(7)
N2
0.046(8)
N3
0.046(7)
CI
0.036(8)
C2
0.041(8)
C3
0.039(9)
C4
0.051(11)
C5
0.070(11)
C6
0.062(10)
C7
0.032(8)
C8
0.065(10)
C9
0.073(11)
CIO
0.077(12)
Cll
0.068(11)
C12
0.040(8)
C13
0.057(9)
C14
0.049(8)
C15
0.115(15)
C16
0.107(14)
C17
0.080(12)
C18
0.082(11)
C19
0.056(9)
C20
0.054(10)
C21
0.081(12)
C22
0.094(14)
C23
0.084(12)
C24
0.043(9)
C25
0.088(12)
C26
0.056(9)
U22
0.0318(3)
0.045(2)
0.052(3)
0.052(3)
0.035(7)
0.028(6)
0.038(7)
0.039(8)
0.056(10)
0.11(2)
0.12(2)
0.060(10)
0.049(11)
0.036(9)
0.048(10)
0.024(8)
0.034(9)
0.057(11)
0.034(9)
0.044(9)
0.045(10)
0.032(10)
0.042(10)
0.065(12)
0.076(12)
0.070(11)
0.11(2)
0.090(13)
0.12(2)
0.10(2)
0.071(13)
0.085(12)
0.058(9)
U33
0.0298(3)
0.041(2)
0.038(2)
0.043(2)
0.049(7)
0.028(5)
0.035(6)
0.042(8)
0.064(9)
0.060(10)
0.050(10)
0.050(9)
0.045(8)
0.037(8)
0.044(9)
0.066(11)
0.071(11)
0.056(10)
0.038(8)
0.035(8)
0.068(9)
0.12(2)
0.086(13)
0.101(13)
0.045(8)
0.041(8)
0.105(14)
0.055(10)
0.084(13)
0.051(9)
0.100(12)
0.042(9)
0.062(9)
U12
0.0030(4)
0.000(2)
0.004(2)
0.005(2)
0.010(5)
0.002(5)
0.003(6)
-0.007(7)
-0.009(8)
-0.027(12)
0.011(12)
0.022(10)
0.022(8)
0.017(6)
0.011(9)
-0.018(8)
0.001(8)
-0.003(9)
0.003(6)
0.005(7)
0.002(8)
-0.010(10)
0.004(10)
-0.035(11)
-0.004(11)
-0.017(8)
0.018(11)
0.000(11)
0.050(13)
-0.006(11)
0.007(8)
0.027(10)
0.011(9)
U13
0.0078(2)
0.015(2
0.012(2
0.003(2
0.024(6
0.012(6
-0.007(5
0.003(6
0.021(7
-0.000(7
0.012(8
-0.001(8
0.005(7
-0.001(6
0.005(8
0.005(9
0.014(9
0.016(9
0.001(6
0.022(7
0.024(7
0.040(13)
0.016(1
0.031(10)
0.026(8
0.018(7
0.026(9
-0.001(9
-0.023(1
-0.007(8
0.017(8
0.019(8
0.021(7
)
)
U23
0.0020(4)
-0.001(2)
-0.003(2)
0.010(2)
0.000(6)
-0.006(5)
0.016(6)
0.001(7)
-0.016(9)
-0.011(13)
0.025(12)
0.018(9)
0.014(7)
0.006(6)
-0.010(8)
-0.002(8)
0.006(9)
-0.003(9)
0.004(6)
0.001(7)
0.003(9)
-0.022(10)
0.015(10)
0.008(11)
0.006(9)
-0.007(8)
0.001(12)
-0.000(10)
-0.019(12)
0.036(10)
-0.012(10)
0.011(9)
-0.001(9)
fl Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor
expression
exp[-27i 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)]
129
atoms of compound 36.
J-^-J- AA.IM.J. l/iu W.J.J.JlWl.^.'.l. U
Atom
X
v
z
u
H2
-0.42722
0.05235
-0.13645
0.08
H3
-0.54983
0.08306
-0.24286
0.08
H4
-0.59452
0.27668
-0.2795
0.08
H5
-0.53144
0.43207
-0.20612
0.08
H6
-0.40926
0.40742
-0.10044
0.08
H8
-0.27357
-0.20739
-0.10841
0.08
H9
-0.34533
-0.35766
-0.07361
0.08
H10
-0.38132
-0.35296
0.04413
0.08
Hll
-0.34192
-0.19235
0.12477
0.08
H13
-0.12276
0.21359
0.10272
0.08
H15a
-0.127290
0.52443
0.13252
0.08
H15b
-0.11236
0.40633
0.17977
0.08
H15c
-0.2064
0.44583
0.13525
0.08
H16a
-0.19522
0.4038
-0.0546
0.08
H16b
-0.17822
0.52277
-0.00837
0.08
H16c
-0.25625
0.44263
-0.00474
0.08
H17a
-0.02728
0.45839
0.05759
0.08
H17b
-0.04195
0.33658
0.01462
0.08
H17c
-0.01102
0.34089
0.10548
0.08
H18a
-0.10114
0.15618
-0.1486
0.08
H18b
-0.08369
0.1644
-0.05838
0.08
H18c
-0.17096
0.21134
-0.11335
0.08
H19a
-0.28215
-0.09034
-0.2038
0.08
H19b
-0.22622
-0.01003
-0.24194
0.08
H19c
-0.29855
0.04603
-0.21029
0.08
H20a
-0.064660
-0.10107
-0.13569
0.08
H20b
-0.11369
-0.18242
-0.09148
0.08
H20c
-0.04566
-0.09078
-0.04542
0.08
H21a
-0.07776
0.11823
0.20648
0.08
H21b
-0.06128
0.0559
0.28723
0.08
H21c
-0.14092
0.13996
0.25745
0.08
H22a
-0.05966
-0.17966
0.22133
0.08
H22b
-0.07223
-0.12558
0.13858
0.08
H22c
-0.13551
-0.22349
0.15141
0.08
H23a
-0.2563
-0.17154
0.24851
0.08
H23b
-0.25518
-0.04549
0.28462
0.08
H23c
-0.17553
-0.129550
0.3144
0.08
H24a
-0.43103
0.03618
0.09071
0.08
H24b
-0.47791
0.1284
0.02796
0.08
H24c
-0.48724
0.13625
0.11238
0.08
H25a
-0.29616
0.13132
0.23158
0.08
H25b
-0.37078
0.21877
0.23374
0.08
H25c
-0.2796
0.26768
0.23438
0.08
H26a
-0.42015
0.37045
0.03424
0.08
H26b
-0.35672
0.41621
0.11183
0.08
H26c
-0.4479
0.3673
0.11118
0.08
130
1
2
3
1-2
1-2-3
H2
C2
C3
0.960(15)
120.1(14)
H2
C2
CI
120.0(11)
H3
C3
C4
0.96(2)
120.5(13)
H3
C3
C2
121.(2)
H4
C4
C5
0.960(14)
119.(2)
H4
C4
C3
120.(2)
H5
C5
C6
0.96(2)
119.3(15)
H5
C5
C4
119.1(14)
H6
C6
CI
0.960(13)
120.7(11)
H6
C6
C5
120.5(14)
H8
C8
C9
0.96(2)
118.5(14)
H8
C8
C7
118.6(14)
H9
C9
CIO
0.960(14)
119.6(15)
H9
C9
C8
120.(2)
H10
CIO
Cll
0.96(2)
121.(2)
H10
CIO
C9
120.6(15)
Hll
Cll
C12
0.96(2)
118.4(14)
Hll
Cll
CIO
118.(2)
H13
C13
C14
0.960(11)
105.8(11)
H13
C13
W
105.8(10)
H15a
C15
H15b
0.960(15)
109.5(14)
H15a
C15
H15c
109.(2)
H15a
C15
C14
110.(2)
H15b
C15
H15c
0.960(15)
109.(2)
H15b
C15
C14
109.3(14)
H15c
C15
C14
0.96(2)
109.5(13)
H16a
C16
HI 6b
0.96(2)
109.(2)
H16a
C16
HI 6c
109.5(14)
H16a
C16
C14
109.4(14)
H16b
C16
HI 6c
0.96(2)
109.(2)
H16b
C16
C14
109.7(12)
HI 6c
C16
C14
0.96(2)
109.3(14)
H17a
C17
H17b
0.96(2)
109.(2)
H17a
C17
H17c
109.5(13)
H17a
C17
C14
109.8(14)
H17b
C17
H17c
0.96(2)
109.(2)
H17b
C17
C14
109.3(12)
H17c
C17
C14
0.960(14)
109.3(15)
H18a
C18
H18b
0.960(15)
109.5(14)
H18a
C18
H18c
109.5(13)
H18a
C18
Si2
109.5(11)
H18b
C18
H18c
0.960(11)
109.5(14)
H18b
C18
Si2
109.4(11)
H18c
C18
Si2
0.960(14)
109.5(11)
131
Table B-17 continued.
H19a
C19
H19b
H19a
C19
H19c
H19a
C19
Si2
H19b
C19
H19c
H19b
C19
Si2
H19c
C19
Si2
H20a
C20
H20b
H20a
C20
H20c
H20a
C20
Si2
H20b
C20
H20c
H20b
C20
Si2
H20c
C20
Si2
H21a
C21
H21b
H21a
C21
H21c
H21a
C21
Si3
H21b
C21
H21c
H21b
C21
Si3
H21c
C21
Si3
H22a
C22
H22b
H22a
C22
H22c
H22a
C22
Si3
H22b
C22
H22c
H22b
C22
Si3
H22c
C22
Si3
H23a
C23
H23b
H23a
C23
H23c
H23a
C23
Si3
H23b
C23
H23c
H23b
C23
Si3
H23c
C23
Si3
H24a
C24
H24b
H24a
C24
H24c
H24a
C24
PI
H24b
C24
H24c
H24b
C24
PI
H24c
C24
PI
H25a
C25
H25b
H25a
C25
H25c
H25a
C25
PI
H25b
C25
H25c
H25b
C25
PI
H25c
C25
PI
H26a
C26
H26b
H26a
C26
H26c
H26a
C26
PI
H26b
C26
H26c
H26b
C26
PI
H26c
C26
PI
0.960(14)
0.960(14)
0.960(14)
0.96(2)
0.96(2)
0.960(14)
0.96(2)
0.960(13)
0.96(2)
0.960(14)
0.96(2)
0.96(2)
0.960(15)
0.96(2)
0.960(12)
0.960(14)
0.960(14)
0.96(2)
0.96(2)
0.96(2)
0.960(15)
0.960(13)
0.960(13)
0.960(15)
109.5(13)
109.5(13)
109.5(9)
109.5(13)
109.4(9)
109.5(10)
109.(2)
109.5(14)
109.4(12)
109.(2)
109.5(11)
109.4(13)
109.5(15)
109.5(15)
109.6(11)
109.5(14)
109.4(12)
109.5(11)
109.(2)
109.(2)
109.5(14)
109.(2)
109.5(13)
109.4(13)
109.5(15)
109.5(15)
109.5(11)
109.5(14)
109.4(12)
109.4(12)
109.5(14)
109.(2)
109.5(9)
109.5(12)
109.6(12)
109.4(11)
109.(2)
109.5(13)
109.4(11)
109.5(15)
109.4(9)
109.6(12)
109.5(14)
109.5(11)
109.6(11)
109.5(14)
109.4(9)
109.5(11)
132
-3-
CO
cn
CO
o
O
133
CrvstaUographic data for f rfMe^SiNbC^ m iWH^Uii-HYfi-
NPh) 2 f rfMe^SiNb C^KU IWfCH^CMe^K 45
Table B-18: CrvstaUographic data for 45
A. Crystal data (298 K)
45
a, A
11.430(1)
b, A
11.640(1)
c, A
19.012 (2)
a, deg.
96.52 (1)
P, deg.
92.39 (1)
y, deg.
104.44 (1)
V,A3
2427.2 (4)
dcaic, g cm" 3 (298 K)
1.532
Empirical formula
C4lH6 8 N6Si4W2
Formula wt, g
1125.07
Crystal system
Triclinic
Space group
P-l
Z
2
F(000), electrons
1120
Crystal size (mm 3 )
0.34 x 0.30 x 0.25
B. Data collection (298 K)
Radiation, X (A)
Mo-Ka, 0.71073
Mode
co-scan
Scan range
Symmetrically over 1.2°
about K a i 2 maximum
Background
offset 1.0 and -1.0 in co from
K al; 2 max i mum
Scan rate, deg. min." 1
3-6
29 range, deg.
3-45
Range of h k I
< h < 12
-12 < k < 12
-20 < I < 20
Total reflections measured
7033
Unique reflections
6235
Absorption coeff. \i (Mo-K a ), cm" 1
4.84
Min. & Max. Transmission
0.365, 0.537
C. Structure refinement
S, Goodness-of-fit
1.11
Reflections used, I > 2a(I)
4878
No. of variables
482
R, wR* (%)
0.0293, 0.0328
134
Table B-18: Crystallographic data for 45. continued
Rint. (%) 0.0119
Max. shift/esd 0.0006
min. peak in diff. four, map (e A" 3 ) -0.993
max. peak in diff. four, map (e A" 3 ) 1 .63 1
* Relevant expressions are as follows, where in the footnote F and F c represent, respectively, the
observed and calculated structure-factor amplitudes.
Function minimized was w(IF l - IF C I) 2 , where w= (g(F))~ 2
R = I(HF l-IFcll)/ElF l
wR = [Iw(IF l - IF C I) 2 / 1 IFqI 2 ] 1 ^ 2
S = [Iw(IF l-IF c l) 2 /(m-n)] 1 / 2
135
Table B-19: Fractiona l coordinates and equivalent isotropic^-thermal parameters (kh for
the non-H atoms of compound 45.
Atom
Wl
0.23216(3)
W2
0.31577(3)
Sil
0.2917(2)
Si2
0.4317(3)
Si3
0.6162(2)
Si4
0.1192(2)
Nl
0.2352(5)
N2
0.3082(6)
N3
0.4762(6)
N4
0.2633(6)
N5
0.2759(5)
N6
0.1935(5)
CI
0.0445(6)
C2
-0.0453(8)
C3
-0.0743(9)
C4
-0.1649(8)
C5
-0.0001(10)
C6
0.2320(7)
C7
0.2721(7)
C8
0.2721(9)
C9
0.2320(10)
CIO
0.1907(10)
Cll
0.1911(9)
C12
0.5130(9)
C13
0.3790(12)
C14
0.5455(10)
C15
0.3523(9)
C16
0.1730(10)
C17
0.4230(9)
C18
0.1238(7)
C19
0.0357(7)
C20
-0.0338(9)
C21
-0.0141(11)
C22
0.0702(11)
C23
0.1406(9)
C24
0.2816(7)
C25
0.2324(7)
C26
0.2420(9)
C27
0.3013(9)
C28
0.3475(9)
C29
0.3375(8)
C30
0.4707(8)
C31
0.3588(7)
C32
0.3462(8)
C33
0.4433(10)
C34
0.5504(9)
C35
0.5655(8)
0.11989(2)
0.28833(3)
0.2682(2)
-0.0668(3)
0.4336(2)
0.3415(3)
0.1410(5)
-0.0138(5)
0.4110(6)
0.3718(6)
0.1199(5)
0.2825(5)
0.0298(7)
-0.0796(8)
-0.0540(11)
-0.1021(8)
-0.1893(9)
0.0299(7)
-0.0532(7)
-0.1637(8)
-0.1926(9)
-0.1117(9)
-0.0001(8)
0.0165(10)
-0.2252(9)
-0.0475(11)
0.4132(7)
0.2897(9)
0.2387(9)
0.3553(6)
0.3128(8)
0.3842(9)
0.5007(10)
0.5429(9)
0.4723(8)
0.0485(7)
-0.0735(7)
-0.1460(9)
-0.0945(10)
0.0266(10)
0.0980(8)
0.4899(7)
0.4683(7)
0.5419(7)
0.6314(8)
0.6531(8)
0.5835(7)
0.276090(10)
0.20326(2)
0.44958(12)
0.26414(13)
0.24674(14)
0.07887(13)
0.3831(3)
0.2968(3)
0.1965(3)
0.1238(3)
0.1713(3)
0.2693(3)
0.2408(4)
0.2632(5)
0.3389(5)
0.2160(5)
0.2519(8)
0.4101(4)
0.3643(4)
0.3854(5)
0.4503(5)
0.4940(5)
0.4745(4)
0.1956(5)
0.2240(6)
0.3405(6)
0.4146(5)
0.5101(5)
0.4989(5)
0.2998(4)
0.3446(4)
0.3763(5)
0.3617(6)
0.3164(6)
0.2865(5)
0.1068(4)
0.1008(4)
0.0380(5)
-0.0164(5)
-0.0109(5)
0.0506(4)
0.1442(4)
0.1047(4)
0.0537(4)
0.0403(5)
0.0781(5)
0.1294(5)
U
0.02849(12)
0.03111(13)
0.0485(9)
0.0583(11)
0.0563(10)
0.0547(10)
0.035(2)
0.036(2)
0.041(2)
0.041(3)
0.032(2)
0.035(2)
0.039(3)
0.051(3)
0.099(6)
0.066(4)
0.110(6)
0.040(3)
0.040(3)
0.061(4)
0.073(5)
0.072(5)
0.059(4)
0.075(5)
0.098(6)
0.100(6)
0.066(4)
0.081(5)
0.077(4)
0.035(3)
0.049(3)
0.070(4)
0.085(6)
0.079(5)
0.060(4)
0.035(3)
0.047(3)
0.070(4)
0.071(5)
0.069(5)
0.051(4)
0.043(3)
0.041(3)
0.051(4)
0.062(4)
0.060(4)
0.055(4)
136
Table B- 19 : continued.
C36
0.7328(9)
0.4112(11)
0.1852(6)
0.099(6)
C37
0.6209(9)
0.3282(10)
0.3131(6)
0.093(5)
C38
0.6523(10)
0.5835(9)
0.2994(5)
0.088(5)
C39
0.0529(9)
0.4724(10)
0.0954(5)
0.087(5)
C40
0.1251(9)
0.2961(9)
-0.0178(5)
0.076(5)
C41
0.0148(8)
0.2151(10)
0.1134(6)
0.093(5)
2For anisotropic atoms, the U value is U eq , calculated as U eq = 1/3 LiXj Uy af af A{;
where Ajj is the dot product of the i* and j* direct space unit cell vectors.
137
Table B-20: Bond Lengths (A) and Angles (Sj for the non-H atoms of compound 4$.
1
2
3
1-2
1-2-3
W2
Wl
HI
2.5430(5)
42.3(15)
W2
Wl
Nl
124.0(2)
W2
Wl
N2
127.1(2)
W2
Wl
N5
47.8(2)
W2
Wl
N6
47.6(2)
HI
Wl
Nl
2.19(5)
95.5(13)
HI
Wl
N2
96.(2)
HI
Wl
N5
70.5(13)
HI
Wl
N6
72.(2)
HI
Wl
CI
153.4(15)
Nl
Wl
N2
2.019(6)
80.4(2)
Nl
Wl
N5
165.3(2)
Nl
Wl
N6
92.7(2)
Nl
Wl
CI
104.7(3)
N2
Wl
N5
2.029(7)
96.0(2)
N2
Wl
N6
165.6(2)
N2
Wl
CI
104.6(3)
N5
Wl
N6
2.075(6)
87.4(2)
N5
Wl
CI
90.0(2)
N6
Wl
CI
2.064(6)
89.4(3)
CI
Wl
W2
2.179(6)
111.0(2)
HI
W2
N3
1.74(6)
80.(2)
HI
W2
N4
161.(2)
HI
W2
N5
84.(2)
HI
W2
N6
87.(2)
HI
W2
Wl
58.(2)
N3
W2
N4
2.043(6)
81.4(2)
N3
W2
N5
127.5(3)
N3
W2
N6
131.8(2)
N3
W2
Wl
137.9(2)
N4
W2
N5
2.034(7)
108.0(2)
N4
W2
N6
105.0(3)
N4
W2
Wl
140.7(2)
N5
W2
N6
1.919(5)
96.6(2)
N5
W2
Wl
53.2(2)
N6
W2
Wl
1.912(6)
52.9(2)
Nl
Sil
C15
1.799(6)
115.2(3)
Nl
Sil
C16
111.4(4)
C15
Sil
C16
1.865(9)
107.2(5)
C15
Sil
C17
105.5(4)
C16
Sil
C17
1.860(11)
111.2(5)
C17
Sil
Nl
1.861(11)
106.2(4)
N2
Si2
C12
1.783(7)
115.0(4)
N2
Si2
C13
110.6(5)
C12
Si2
C13
1.854(10)
106.4(5)
C12
Si2
C14
105.8(5)
C13
Si2
C14
1.853(10)
111.6(6)
C14
Si2
N2
1.863(11)
107.2(4)
138
Table B-20: continued
N3
Si3
C36
N3
Si3
C37
C36
Si3
C37
C36
Si3
C38
C37
Si3
C38
C38
Si3
N3
N4
Si4
C39
N4
Si4
C40
C39
Si4
C40
C39
Si4
C41
C40
Si4
C41
C41
Si4
N4
Wl
HI
W2
C6
Nl
C7
N2
Si2
C30
N3
C31
N4
Si4
C24
N5
C18
N6
C3
C2
C4
C4
C2
C5
C5
C2
C3
C7
C6
Cll
C7
C6
Nl
Cll
C6
Nl
C8
C7
N2
C8
C7
C6
N2
C7
C6
C9
C8
C7
CIO
C9
C8
Cll
CIO
C9
C6
Cll
CIO
C19
C18
C23
C19
C18
N6
C23
C18
N6
C20
C19
C18
C21
C20
C19
C22
C21
C20
C23
C22
C21
C18
C23
C22
C25
C24
C29
C25
C24
N5
C29
C24
N5
C26
C25
C24
C27
C26
C25
C28
C27
C26
C29
C28
C27
C24
C29
C28
C31
C30
C35
C31
C30
N3
C35
C30
N3
C32
C31
N4
1.773(7)
108.6(4)
116.2(4)
1.857(12)
104.5(6)
114.1(5)
1.865(12)
104.9(5)
1.850(10)
108.7(4)
1.758(7)
110.7(4)
111.2(4)
1.866(13)
111.6(5)
106.5(5)
1.862(9)
106.9(4)
1.852(11)
109.7(4)
80.(2)
1.437(10)
1.453(10)
113.3(5)
1.438(11)
1.448(9)
118.6(6)
1.414(9)
1.398(10)
1.504(13)
107.3(8)
1.551(12)
107.9(7)
1.489(15)
111.6(10)
1.403(12)
119.6(8)
114.7(7)
1.380(12)
125.6(8)
1.389(13)
126.0(7)
119.2(7)
114.8(7)
1.382(14)
120.8(9)
1.37(2)
119.5(10)
1.390(15)
120.9(9)
120.0(9)
1.380(11)
117.5(8)
121.1(7)
1.380(12)
121.4(7)
1.393(15)
122.0(8)
1.38(2)
118.6(9)
1.36(2)
120.0(12)
1.38(2)
120.9(10)
120.8(9)
1.380(11)
119.4(7)
119.3(7)
1.377(11)
121.2(6)
1.406(13)
119.8(8)
1.373(14)
119.5(9)
1.37(2)
120.6(9)
1.382(13)
119.9(9)
120.7(8)
1.408(12)
118.3(8)
115.8(6)
1.394(11)
126.0(8)
1.390(12)
125.3(7)
139
Table B-20: continued.
C32
C31
C30
119.1(7)
N4
C31
C30
115.5(7)
C33
C32
C31
1.375(12)
120.2(8)
C34
C33
C32
1.345(14)
121.0(9)
C35
C34
C33
1.369(14)
120.2(8)
C30
C35
C34
121.1(8)
140
Table B-21: Anisotropic thermal parameters^ for the non-H atoms of compound 45.
Atom
Ull
U22
U33
U12
U13
U23
Wl
0.0342(2)
0.0276(2)
0.0243(2) 0.0076(2) 0.0029(2)
0.00628(14
W2
0.0329(2)
0.0308(2)
0.0292(2) 0.0049(2) 0.0017(2)
0.0094(2)
Sil
0.067(2)
0.0446(14)
0.0317(1
3) 0.0152(13) -0.0072(12)
-0.0039(11)
Si2
0.069(2)
0.078(2)
0.0453(1
5) 0.047(2)
0.0119(13)
0.0162(13)
Si3
0.0396(14)
0.063(2)
0.058(2)
-0.0024(1
.2) -0.0028(12)
0.0127(13)
Si4
0.0430(14)
0.079(2)
0.0471(1
5) 0.0159(1
.3) -0.0014(12)
0.0320(14)
Nl
0.043(4)
0.032(4)
0.030(3)
0.011(3)
0.005(3)
0.004(3)
N2
0.046(4)
0.038(4)
0.029(3)
0.018(3)
0.005(3)
0.009(3)
N3
0.036(4)
0.042(4)
0.040(4)
-0.000(3)
0.006(3)
0.009(3)
N4
0.041(4)
0.043(4)
0.039(4)
0.007(3)
0.008(3)
0.014(3)
N5
0.032(3)
0.031(3)
0.034(4)
0.010(3)
-0.002(3)
0.004(3)
N6
0.040(4)
0.030(3)
0.035(4)
0.008(3)
-0.005(3)
0.005(3)
CI
0.032(4)
0.043(5)
0.037(5)
-0.004(4)
0.002(4)
0.021(4)
C2
0.044(5)
0.047(5)
0.061(6)
0.002(4)
0.007(4)
0.018(4)
C3
0.062(7)
0.149(12)
0.060(7)
-0.026(7)
0.007(6)
0.026(7)
C4
0.045(6)
0.064(6)
0.073(7)
-0.014(5)
-0.003(5)
0.009(5)
C5
0.067(8)
0.056(7)
0.197(1!
i) -0.013(6)
-0.014(9)
0.042(8)
C6
0.055(5)
0.040(5)
0.028(4)
0.013(4)
0.009(4)
0.007(4)
C7
0.045(5)
0.047(5)
0.032(4)
0.011(4)
-0.007(4)
0.019(4)
C8
0.096(8)
0.049(6)
0.050(6)
0.036(5)
0.011(5)
0.021(5)
C9
0.118(9)
0.047(6)
0.063(7)
0.028(6)
0.008(6)
0.031(5)
CIO
0.100(8)
0.075(7)
0.044(6)
0.017(6)
0.015(6)
0.032(6)
Cll
0.088(7)
0.051(6)
0.036(5)
0.014(5)
0.010(5)
0.008(4)
C12
0.069(7)
0.114(9)
0.060(6)
0.054(7)
0.017(5)
0.020(6)
C13
0.169(13)
0.073(8)
0.080(8)
0.078(8)
0.026(8)
0.015(6)
C14
0.087(8)
0.160(12)
0.079(8)
0.066(8)
0.009(7)
0.050(8)
C15
0.082(7)
0.052(6)
0.053(6)
0.006(5)
-0.020(5)
-0.009(5)
C16
0.127(10)
0.075(7)
0.049(6)
0.047(7)
0.008(6)
-0.001(5)
C17
0.084(8)
0.071(7)
0.064(7)
0.006(6)
-0.032(6)
0.004(5)
C18
0.043(5)
0.030(4)
0.036(5)
0.013(4)
0.004(4)
0.011(4)
C19
0.050(5)
0.046(5)
0.053(5)
0.018(4)
0.012(5)
-0.005(4)
C20
0.058(6)
0.080(8)
0.073(7)
0.025(6)
0.013(5)
-0.002(6)
C21
0.093(9)
0.087(9)
0.093(9)
0.065(8)
0.010(7)
-0.009(7)
C22
0.109(10)
0.055(7)
0.089(8)
0.051(7)
-0.002(7)
0.008(6)
C23
0.081(7)
0.045(6)
0.060(6)
0.026(5)
-0.002(5)
0.007(5)
C24
0.036(4)
0.036(5)
0.035(5)
0.013(4)
-0.001(4)
-0.003(4)
C25
0.042(5)
0.055(6)
0.040(5)
0.006(4)
0.003(4)
0.001(4)
C26
0.072(7)
0.057(6)
0.070(7)
0.012(5)
-0.012(6)
-0.014(6)
C27
0.084(8)
0.093(9)
0.037(6)
0.034(7)
-0.001(5)
-0.012(6)
C28
0.090(8)
0.091(8)
0.039(6)
0.047(7)
0.022(5)
0.004(5)
C29
0.073(6)
0.061(6)
0.029(5)
0.029(5)
0.022(4)
0.018(4)
C30
0.053(6)
0.032(5)
0.051(5)
0.015(4)
0.025(5)
0.013(4)
C31
0.050(5)
0.039(5)
0.042(5)
0.019(4)
0.016(4)
0.016(4)
C32
0.068(6)
0.045(5)
0.047(5)
0.021(5)
0.003(5)
0.021(4)
C33
0.085(8)
0.051(6)
0.054(6)
0.012(6)
0.021(6)
0.029(5)
C34
0.067(7)
0.051(6)
0.061(6)
0.001(5)
0.029(6)
0.022(5)
C35
0.060(6)
0.043(5)
0.058(6)
0.000(5)
0.017(5)
0.010(5)
C36
0.052(7)
0.123(10)
0.121(11
) 0.020(7)
0.005(7)
0.021(8)
141
Table B-21: continued.
C37
C38
C39
C40
C41
0.060(7)
0.092(8)
0.079(8)
0.069(7)
0.051(6)
0.111(9)
0.079(8)
0.137(10)
0.095(8)
0.138(11)
0.106(9)
0.068(7)
0.070(7)
0.061(7)
0.084(8)
0.003(6)
-0.022(6)
0.058(7)
0.018(6)
-0.001(6)
-0.025(6)
-0.012(6)
0.012(6)
-0.017(5)
-0.025(6)
0.053(8)
0.005(6)
0.048(7)
0.013(6)
0.054(8)
3 Uij are the mean-square amplitudes of vibration in A 2 from the general temperature factor expressic
exp[-27t 2 (h 2 a* 2 Ull + k 2 b* 2 U22 + l 2 c* 2 U33 + 2hka*b*U12 + 2hla*c*U13 + 2klb*c*U23)]
142
Table B-22: Fractional coordinates and isotropic-thermal parameters (A2) for the H atoms of
compound 45.
Atom
HI
0.404(5)
Hla
0.04745
Hlb
0.00337
H3a
-0.00196
H3b
-0.1336
H3c
-0.10576
H4a
-0.19577
H4b
-0.22332
H4c
-0.14943
H5a
0.07397
H5b
0.01432
H5c
-0.05958
H8
0.30009
H9
0.23332
H10
0.16127
Hll
0.16265
H12a
0.4583
H12b
0.57922
H12c
0.54353
H13a
0.33616
H13b
0.44759
H13c
0.3261
H14a
0.61348
H14b
0.50937
H14c
0.57217
H15a
0.28831
H15b
0.4154
H15c
0.38447
H16a
0.1397
H16b
0.10986
HI 6c
0.20825
H17a
0.45662
H17b
0.48355
H17c
0.39661
H19
0.02177
H20
-0.09417
H21
-0.06001
H22
0.0811
H23
0.20209
H25
0.19178
H26
0.20735
H27
0.31052
H28
0.38671
H29
0.37004
H32
0.26931
H33
0.43462
H34
0.61651
u
0.253(5)
0.270(3)
0.011(14)
0.00848
0.1907
0.08
0.0922
0.24846
0.08
-0.03966
0.36964
0.08
-0.12142
0.35135
0.08
0.01536
0.34398
0.08
-0.032390
0.22229
0.08
-0.16926
0.22938
0.08
-0.11847
0.16711
0.08
-0.17747
0.28063
0.08
-0.20514
0.20278
0.08
-0.25592
0.26504
0.08
-0.22066
0.35439
0.08
-0.26875
0.46464
0.08
-0.13233
0.53861
0.08
0.05609
0.50585
0.08
0.00964
0.15475
0.08
-0.01627
0.18224
0.08
0.09928
0.21444
0.08
-0.27209
0.25773
0.08
-0.25452
0.21104
0.08
-0.23108
0.18246
0.08
-0.07528
0.32471
0.08
-0.09287
0.3767
0.08
0.03559
0.35928
0.08
0.43343
0.38841
0.08
0.40581
0.38393
0.08
0.47481
0.45347
0.08
0.21655
0.52911
0.08
0.31189
0.48418
0.08
0.35188
0.54816
0.08
0.30448
0.53524
0.08
0.2299
0.46668
0.08
0.16662
0.520260
0.08
0.23153
0.3543
0.08
0.35316
0.40767
0.08
0.55191
0.38354
0.08
0.62294
0.30494
0.08
0.50492
0.256180
0.08
-0.10875
0.13925
0.08
-0.23083
0.03316
0.08
-0.14399
-0.05873
0.08
0.06209
-0.04978
0.08
0.18302
0.05424
0.08
0.53024
0.02782
0.08
0.67914
0.00339
0.08
0.7177
0.06909
0.08
143
Table B-22: continued.
H35
0.64259
0.59926
0.15572
0.08
H36a
0.73586
0.46294
0.14901
0.08
H36b
0.71233
0.32944
0.16349
0.08
H36c
0.81035
0.4295
0.21114
0.08
H37a
0.70114
0.34614
0.33573
0.08
H37b
0.59956
0.24763
0.28949
0.08
H37c
0.56448
0.33664
0.34809
0.08
H38a
0.65146
0.6428
0.26831
0.08
H38b
0.7312
0.59958
0.32359
0.08
H38c
0.59311
0.58575
0.33351
0.08
H39a
0.10425
0.5405
0.07826
0.08
H39b
0.04634
0.49015
0.14539
0.08
H39c
-0.02609
0.45386
0.07097
0.08
H40a
0.17851
0.35955
-0.03775
0.08
H40b
0.04535
0.27976
-0.04094
0.08
H40c
0.15442
0.22545
-0.02445
0.08
H41b
-0.063710
0.19883
0.08873
0.08
H41c
0.00847
0.23537
0.16321
0.08
H41D
0.04561
0.14539
0.10611
0.08
144
1
2
3
1-2
1-2-3
Hla
CI
Hlb
0.960(7)
109.5(8)
H3a
C3
H3b
0.960(10)
109.5(11)
H3a
C3
H3c
109.5(10)
H3a
C3
C2
109.5(9)
H3b
C3
H3c
0.960(11)
109.5(11)
H3b
C3
C2
109.5(9)
H3c
C3
C2
0.960(13)
109.4(10)
H4a
C4
H4b
0.960(10)
109.5(9)
H4a
C4
H4c
109.5(10)
H4a
C4
C2
109.5(7)
H4b
C4
H4c
0.960(8)
109.5(8)
H4b
C4
C2
109.5(9)
H4c
C4
C2
0.960(9)
109.4(8)
H5a
C5
H5b
0.960(12)
109.5(12)
H5a
C5
H5c
109.5(13)
H5a
C5
C2
109.4(9)
H5b
C5
H5c
0.960(14)
109.5(10)
H5b
C5
C2
109.6(11)
H5c
C5
C2
0.960(10)
109.4(10)
H8
C8
C9
0.960(10)
119.6(9)
H8
C8
C7
119.6(9)
H9
C9
CIO
0.960(11)
120.3(10)
H9
C9
C8
120.2(10)
H10
CIO
Cll
0.960(10)
119.5(10)
HIO
CIO
C9
119.6(11)
Hll
Cll
C6
0.960(9)
120.0(9)
Hll
Cll
CIO
120.0(9)
H12a
C12
H12b
0.960(10)
109.5(9)
HI 2a
C12
H12c
109.5(11)
H12a
C12
Si2
109.5(7)
HI 2b
C12
H12c
0.960(11)
109.5(9)
H12b
C12
Si2
109.4(9)
HI 2c
C12
Si2
0.960(10)
109.5(7)
H13a
C13
H13b
0.960(11)
109.5(12)
H13a
C13
H13c
109.5(11)
H13a
C13
Si2
109.4(8)
H13b
C13
H13c
0.960(14)
109.5(11)
H13b
C13
Si2
109.5(8)
H13c
C13
Si2
0.960(12)
109.5(9)
H14a
C14
H14b
0.960(13)
109.5(13)
H14a
C14
H14c
109.5(10)
H14a
C14
Si2
109.4(8)
H14b
C14
H14c
0.960(11)
109.5(10)
H14b
C14
Si2
109.5(8)
H14c
C14
Si2
0.960(12)
109.5(10)
H15a
C15
H15b
0.960(10)
109.5(9)
H15a
C15
H15c
109.5(9)
H15b
C15
H15c
0.960(10)
109.5(9)
145
Table B-23: continued.
H16a
C16
H16b
0.960(10)
109.5(10)
H16a
C16
HI 6c
109.5(9)
H16b
C16
HI 6c
0.960(12)
109.5(11)
H17a
C17
H17b
0.960(9)
109.5(9)
H17a
C17
H17c
109.5(9)
H17b
C17
H17c
0.960(10)
109.5(11)
H19
C19
C20
0.960(9)
119.0(8)
H19
C19
C18
119.0(9)
H20
C20
C21
0.960(10)
120.6(11)
H20
C20
C19
120.7(10)
H21
C21
C22
0.960(13)
119.9(12)
H21
C21
C20
120.0(11)
H22
C22
C23
0.960(11)
119.5(11)
H22
C22
C21
119.6(13)
H23
C23
C18
0.960(9)
119.6(10)
H23
C23
C22
119.6(9)
H25
C25
C26
0.960(8)
120.1(8)
H25
C25
C24
120.1(8)
H26
C26
C27
0.960(10)
120.3(10)
H26
C26
C25
120.3(10)
H27
C27
C28
0.960(10)
119.7(10)
H27
C27
C26
119.7(10)
H28
C28
C29
0.960(10)
120.1(10)
H28
C28
C27
120.0(10)
H29
C29
C24
0.960(9)
119.7(8)
H29
C29
C28
119.6(8)
H32
C32
C33
0.960(9)
119.9(9)
H32
C32
C31
119.9(8)
H33
C33
C34
0.960(10)
119.5(9)
H33
C33
C32
119.5(10)
H34
C34
C35
0.960(9)
119.9(10)
H34
C34
C33
119.9(10)
H35
C35
C30
0.960(9)
119.4(9)
H35
C35
C34
119.5(8)
H36a
C36
H36b
0.960(13)
109.5(11)
H36a
C36
H36c
109.5(10)
H36b
C36
H36c
0.960(12)
109.5(13)
H37a
C37
H37b
0.960(10)
109.5(12)
H37a
C37
H37c
109.5(11)
H37b
C37
H37c
0.960(11)
109.5(10)
H38a
C38
H38b
0.960(11)
109.5(9)
H38a
C38
H38c
109.5(12)
H38b
C38
H38c
0.960(11)
109.5(10)
H39a
C39
H39b
0.960(11)
109.5(10)
H39a
C39
H39c
109.5(12)
H39a
C39
Si4
109.5(9)
H39b
C39
H39c
0.960(10)
109.5(11)
H39b
C39
Si4
109.5(9)
H39c
C39
Si4
0.960(10)
109.5(8)
146
Table B-23: continued.
H40a
C40
H40b
H40a
C40
H40c
H40a
C40
Si4
H40b
C40
H40c
H40b
C40
Si4
H40c
C40
Si4
H41b
C41
H41c
H41b
C41
H41D
H41b
C41
Si4
H41c
C41
H41D
H41c
C41
Si4
H41D
C41
Si4
0.960(10)
109.5(10)
109.5(10)
109.5(7)
0.960(10)
109.5(9)
109.5(8)
0.960(12)
109.5(8)
0.960(10)
109.5(10)
109.5(10)
109.5(9)
0.960(11)
109.5(12)
109.5(7)
0.960(12)
109.4(8)
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BIOGRAPHICAL SKETCH
Daniel David VanderLende became enamored with chemistry while testing
pool water samples for Acme Pool Service in the summer of 1984. The challenge
presented to him by the excellent teaching of Donald Hopwood at Creston High School
inspired Dan to continue his chemical education at the College of Wooster. Dr. Ted
Williams took the time to provoke, inspire, tolerate, and nurture Dan as both a chemist and
a person. Dr. Paul Gaus introduced Dan to synthetic organometallic chemistry in 1989 and
instilled in him the pride and perseverance to make air-sensitive materials. Paul also
explained to Dan that graduate school wasn't for just the A' student. Graduate school,
according to Dr. Gaus, was for the person who wanted to give what it took to get the job
done. He proved to be correct.
After considering offers from numerous professional sports teams, Dan realized
that his graduate education was more important. After spending the summer of 1990 in
Wooster as a PRF Researcher, Dan's love of synthesis drove him to the University of
Florida. Once Dan recovered from a debilitating bicycle/auto accident, he began to create
new molecules in the laboratory of his mentor, Dr. Jim Boncella.
Over four years, Dan made strides in group(lO) amide chemistry as well as high
oxidation state tungsten chemistry. Although few people understand what drives Dan to
spend long hours trying to prepare new compounds, the reason is simple. Dan will never
hold the world record in the 100 yard dash, hit 716 home runs, or be the first man on the
moon. But the feeling might be the same as standing there holding a Schlenk tube
containing crystals of W(NPh)Cl 2 (Me3SiN)2C6H4.
153
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality as a thesis
for the degree of Doctor of Philosophy.
t&mPh fpHh^J^U
ames M. Boncella, Chair
Associate Professor of Chemistry
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis
for the degree of Doctor of Philosophy.
David E. Richardson
Professor of Chemistry
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis
for the degree of Doctor of Philosophy.
William M. Jones
Disinguished Service"Professor of
Chemistry
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis
for the degree of Doctor of Philosophy.
Kenneth B. Wagener I
Professor of Chemistry
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis
for the degree of Doctor of Philosophy.
Anthony/6. Brennan
Assistant Professor of Materials
Science and Engineering
This thesis was submitted to the Graduate Faculty of the of the Department of
Chemistry in the College of Liberal Arts and Sciences and to the Graduate School and was
accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy
December, 1994
Dean, Graduate School
